Keyword: experiment
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MOZGBD1 Towards Full Performance Operation of SwissFEL FEL, photon, electron, laser 24
 
  • T. Schietinger
    PSI, Villigen PSI, Switzerland
  
  Swiss­FEL is the new X-ray free-elec­tron laser fa­cil­ity at the Paul Scher­rer In­sti­tute (PSI) in Switzer­land. It was in­au­gu­rated in De­cem­ber 2016 and saw its first pilot ex­per­i­ments at the end of 2017. We de­scribe the com­mis­sion­ing steps lead­ing to the first phase of pilot ex­per­i­ments and out­line the plans to­wards reach­ing nom­i­nal per­for­mance lev­els in 2018.  
slides icon Slides MOZGBD1 [11.391 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOZGBD1  
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MOZGBE5 Results on the FCC-hh Beam Screen at the KIT Electron Storage Ring KARA photon, electron, radiation, vacuum 55
 
  • L.A. Gonzalez, V. Baglin, P. Chiggiato, C. Garion, M. Gil Costa, R. Kersevan
    CERN, Geneva, Switzerland
  • I. Bellafont, F. Pérez
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  • S. Casalbuoni, E. Huttel
    KIT, Eggenstein-Leopoldshafen, Germany
  
  Funding: * The European Circular Energy-Frontier Collider Study (EuroCirCol) project has received funding from the European Union's Horizon 2020 research and innovation programme under grant No 654305.
In the frame­work of the Eu­ro­Cir­Col col­lab­o­ra­tion* (work pack­age 4 "Cryo­genic Beam Vac­uum Sys­tem"), the fab­ri­ca­tion of 3 FCC-hh beam-screen (BS) pro­to­types has been car­ried out with the aim of test­ing them at room tem­per­a­ture at the Karl­sruhe In­sti­tute of Tech­nol­ogy (KIT) 2.5 GeV elec­tron stor­age ring KARA (KArl­sruhe Re­search Ac­cel­er­a­tor). The 3 BS pro­to­types will be tested on a beam­line in­stalled by the col­lab­o­ra­tion, named as BEam Screen TEst­bench EX­per­i­ment (BESTEX). KARA has been cho­sen be­cause its syn­chro­tron ra­di­a­tion (SR) spec­trum, pho­ton flux and power, match the one fore­seen for the 50+50 TeV FCC-hh pro­ton col­lider. Each of the 3 BS pro­to­types, 2 m in length, im­ple­ment a dif­fer­ent de­sign fea­ture: 1) base­line de­sign (BD), with elec­tro-de­posited cop­per and no elec­tron-cloud (EC) mit­i­ga­tion fea­tures; 2) BD with set of dis­trib­uted cold-sprayed anti-EC clear­ing elec­trodes; 3) BD with laser-ab­lated anti-EC sur­face tex­tur­ing. We pre­sent here the re­sults ob­tained so far at BESTEX and the com­par­i­son with ex­ten­sive mon­te­carlo sim­u­la­tions of the ex­pected out­gassing be­hav­ior under syn­chro­tron ra­di­a­tion.
The information herein only reflects the views of its authors and the European Commission is not responsible for any use that may be made of the information.
 		 
slides icon Slides MOZGBE5 [4.318 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOZGBE5  
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MOZGBF3 40 Years of Electron Cooling at CERN electron, proton, antiproton, gun 69
 
  • G. Tranquille
    CERN, Geneva, Switzerland
  
  For nearly 40 years elec­tron cool­ing has been used ex­ten­sively on the stor­age rings of the CERN ac­cel­er­a­tor com­plex for the ac­cu­mu­la­tion of ions or for the im­prove­ment of beam qual­ity for pre­ci­sion ex­per­i­ments. Since the first cool­ing ex­per­i­ments on ICE the cool­ers have evolved to in­cor­po­rate the lat­est ad­vances in elec­tron cool­ing tech­nol­ogy and many unique ex­per­i­ments have also been per­formed when the cool­ers are not used for every­day op­er­a­tion. The trap­ping of anti-hy­dro­gen atoms and more re­cently lead-lead and pro­ton-lead ion col­li­sions in the LHC have been made pos­si­ble thanks to cool­ing in the AD and cool­ing and ac­cu­mu­la­tion of lead ions in the LEIR re­spec­tively. The next cooler to be built at CERN will be in­stalled on ELENA and will op­er­ate at elec­tron en­er­gies below 350 eV. Many chal­lenges lie ahead in op­er­at­ing at such a low en­ergy with min­i­mum per­tur­ba­tion to the stor­age ring. The pre­sent AD cooler, which has al­ready seen two re-in­car­na­tions, will also be re­placed with a new state-of-the-art de­vice op­er­at­ing at higher en­er­gies in order to im­prove the qual­ity of the an­tipro­ton beam in this ring.  
slides icon Slides MOZGBF3 [14.902 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOZGBF3  
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MOPMF006 Test of Stepwise Electron Bunch Replacement in eRHIC Using an Electron Lens in RHIC electron, emittance, proton, simulation 95
 
  • W. Fischer, M.R. Costanzo, A.V. Fedotov, X. Gu, A. Marusic, M.G. Minty, C. Montag, Y. Tan, P. Thieberger
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy.
The elec­tron-ion col­lider eRHIC re­quires an elec­tron bunch re­place­ment about every sec­ond to main­tain both high lu­mi­nos­ity and po­lar­iza­tion. If the bunch can be re­placed in sev­eral steps, the re­quire­ments for both the elec­tron gun and the elec­tron ac­cel­er­a­tor are greatly re­duced due to the re­duced bunch charge. How­ever, a step­wise re­place­ment of elec­tron bunches in eRHIC will give rise to tran­sient ef­fects from the beam-beam in­ter­ac­tion that will lead to emit­tance growth. Such a scheme was tested using one of the RHIC elec­tron lenses with a mul­ti­ple step in­crease of the elec­tron cur­rent. The test pro­vides an or­der-of-mag­ni­tude es­ti­mate of the ef­fect with­out any fur­ther mit­i­gat­ing mea­sures. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF006  
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MOPMF010 Measurement and Simulation of Betatron Coupling Beam Transfer Function in RHIC coupling, betatron, simulation, quadrupole 99
 
  • Y. Luo, W. Fischer, A. Marusic, M.G. Minty
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Trans­fer func­tion mea­sure­ments are im­por­tant for char­ac­ter­iz­ing be­ta­tron tunes, be­ta­tron cou­pling, and beam spec­trum in the rou­tine op­er­a­tion of the Rel­a­tivis­tic Heavy Ion Col­lider (RHIC). To coun­ter­act the lin­ear be­ta­tron cou­pling, we de­vel­oped a tech­nique to con­tin­u­ously mea­sure the be­ta­tron cou­pling co­ef­fi­cient with a base band phase lock loop tune meter in 2006. Based on this tech­nique, we demon­strated and built a ro­bust tune/cou­pling feed­back in RHIC. In this ar­ti­cle, we re­visit the BTF mea­sure­ment with be­ta­tron cou­pling to bench­mark our BTF sim­u­la­tion code. We also com­pared the val­ues of eigen­mode pro­jec­tion ra­tios from BTF with those cal­cu­lated with the sin­gle par­ti­cle model. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF010  
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MOPMF039 First Xenon-Xenon Collisions in the LHC luminosity, proton, injection, emittance 180
 
  • M. Schaumann, R. Alemany-Fernández, P. Baudrenghien, T. Bohl, C. Bracco, R. Bruce, N. Fuster-Martínez, M.A. Jebramcik, J.M. Jowett, T. Mertens, D. Mirarchi, S. Redaelli, B. Salvachua, M. Solfaroli, H. Timko, J. Wenninger
    CERN, Geneva, Switzerland
  
  In 2017, the CERN ac­cel­er­a­tor com­plex once again demon­strated its flex­i­bil­ity by pro­duc­ing beams of a new ion species, xenon, that were suc­cess­fully in­jected into LHC. On 12 Oc­to­ber, col­li­sions of fully stripped xenon nu­clei were recorded for the first time in the LHC at a cen­tre-of-mass en­ergy per col­lid­ing nu­cleon pair of 5.44 TeV. Physics data tak­ing started 9.5 h after the first in­jec­tion of xenon beams and lasted a total of 6 h. The in­te­grated lu­mi­nos­ity de­liv­ered to the four LHC ex­per­i­ments was suf­fi­cient that new physics re­sults can be ex­pected soon. We pro­vide a gen­eral overview of this Xe-Xe pilot run be­fore fo­cussing on beam data at in­jec­tion en­ergy and at flat-top.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF039  
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MOPMF040 Crossing Angle Anti-Leveling at the LHC in 2017 luminosity, operation, proton, simulation 184
 
  • N. Karastathis, K. Fuchsberger, M. Hostettler, Y. Papaphilippou, D. Pellegrini
    CERN, Geneva, Switzerland
  
  In 2017, LHC in­cor­po­rated in op­er­a­tion an anti-lev­el­ing pro­ce­dure of adapt­ing in steps the cross­ing angle of the col­lid­ing beams to in­crease the in­te­grated lu­mi­nos­ity. In this paper, we pre­sent the Dy­namic Aper­ture sim­u­la­tions that were em­ployed to iden­tify the op­er­a­tional mar­gins, and there­fore de­fine the lev­el­ing steps. The re­sults are com­ple­mented by ob­ser­va­tions from nom­i­nal op­er­a­tion and pro­jec­tions for the 2018 op­er­a­tion. Ad­di­tional anti-lev­el­ing tech­niques, in­ves­ti­gated in ded­i­cated ma­chine stud­ies are also dis­cussed  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF040  
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MOPMF041 Refining the HL-LHC Operational Settings with Inputs From Dynamic Aperture Simulations: A Progress Report luminosity, octupole, operation, dynamic-aperture 188
 
  • N. Karastathis, R. De Maria, S.D. Fartoukh, Y. Papaphilippou, D. Pellegrini
    CERN, Geneva, Switzerland
  
  Re­cent Dy­namic Aper­ture (DA) sim­u­la­tions aimed at pro­vid­ing guid­ance for the lat­est up­dates of the op­er­a­tional sce­nario for the High Lu­mi­nos­ity up­grade of the LHC. The im­pact of the in­creased chro­matic­ity and oc­tu­pole cur­rent has been as­sessed con­sid­er­ing the lat­est up­dates of the op­tics. Ad­di­tional means to im­prove the life­time, such as tune op­ti­miza­tion, have been iden­ti­fied and de­ployed. We also briefly dis­cuss the im­pact of de­liv­er­ing high lu­mi­nos­ity to the LHCb ex­per­i­ment.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF041  
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MOPMF051 LHC Operational Scenarios During 2017 Run luminosity, proton, optics, hadron 220
 
  • B. Salvachua, M. Albert, R. Alemany-Fernández, T. Argyropoulos, E. Bravin, H. Burkhardt, G.E. Crockford, JCD. Dumont, S.D. Fartoukh, K. Fuchsberger, R. Giachino, M. Giovannozzi, G.H. Hemelsoet, W. Höfle, J.M. Jowett, Y. Le Borgne, D. Nisbet, M. Pojer, L. Ponce, S. Redaelli, M. Solfaroli, R. Suykerbuyk, D.J. Walsh, J. Wenninger, M. Zerlauth
    CERN, Geneva, Switzerland
  
  Dur­ing 2017, the Large Hadron Col­lider LHC de­liv­ered lu­mi­nos­ity for dif­fer­ent physics con­fig­u­ra­tion in ad­dtion to the nom­i­nal 6.5 TeV pro­ton-pro­ton run. About 18.5 days were ded­i­cated to com­mis­sion and to de­liver spe­cial physics to the ex­per­i­ments. Con­di­fu­ra­tions with large beta-star of 19 m and 24 m were pre­pared for lu­mi­nos­ity cal­i­bra­tion with Van de Meer scans. A pro­ton-pro­ton run at 2.51 TeV took place dur­ing the last weeks of No­vem­ber to pro­vide ref­er­ence data for the heavy ion (Pb-Pb, p-Pb) col­li­sions at the same equiv­a­lent nu­cleon en­ergy . A very short (0.5 days) but ef­fec­tive ion run was sched­uled where the LHC saw the first Xe beams col­lis­sions and de­liv­ered around 3 ub-1 to ATLAS and CMS. The run ended with a low event pile-up run at 6.5TeV. This con­tri­bu­tion sum­ma­rizes the op­er­a­tional as­pects and de­liv­ered tar­gets for the dif­fer­ent con­fig­u­ra­tions.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF051  
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MOPMF052 Monitoring and Modeling of the LHC Luminosity Evolution in 2017 luminosity, emittance, operation, monitoring 224
 
  • N. Karastathis, F. Antoniou, I. Efthymiopoulos, M. Hostettler, G. Iadarola, S. Papadopoulou, Y. Papaphilippou, D. Pellegrini, B. Salvachua
    CERN, Geneva, Switzerland
  
  In 2017, the Large Hadron Col­lider (LHC) restarted op­er­a­tion at 6.5 TeV, after an ex­tended end-of-the-year stop, sched­uled to de­liver 45/fb to the two gen­eral-pur­pose ex­per­i­ments. Con­tin­u­ous mon­i­tor­ing of the key beam pa­ra­me­ters and ma­chine con­fig­u­ra­tions that im­pact the de­liv­ered lu­mi­nos­ity was in­tro­duced, pro­vid­ing fast feed­back to op­er­a­tions for fur­ther op­ti­mi­sa­tion. The nu­mer­i­cal model based on sim­u­la­tions and use of se­lected ma­chine pa­ra­me­ters to es­ti­mate the ma­chine lu­mi­nos­ity was fur­ther de­vel­oped. The lu­mi­nos­ity evo­lu­tion and com­par­isons to the model pre­dic­tions is pre­sented in this paper. The im­pact of the dy­namic vari­a­tion of the cross­ing angle, which was in­cor­po­rated into nom­i­nal LHC op­er­a­tion, is also dis­cussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF052  
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MOPMF060 Safe Disposal of the LHC Beam without Beam Dump - Method and Experimental Verification collimation, emittance, controls, dumping 253
 
  • M. Valette, B. Lindstrom, A. Mereghetti, R. Schmidt, M. Solfaroli, J.A. Uythoven, D. Valuch, J. Wenninger, D. Wollmann, M. Zerlauth
    CERN, Geneva, Switzerland
  
  Funding: Research supported by the HL-LHC project.
In the ex­tremely un­likely event of a non-work­ing beam dump­ing sys­tem in the LHC, the 360 MJ of stored beam en­ergy can be dis­si­pated in the col­li­ma­tion sys­tem as a last mit­i­ga­tion mea­sure. In such a sit­u­a­tion, it is im­por­tant to re­duce the stored beam en­ergy both quickly and at the same time as smoothly as pos­si­ble in order to limit the risk of trips of crit­i­cal sys­tems, to avoid quenches of su­per­con­duct­ing mag­nets (which would lead to changes of the beam tra­jec­tory and dam­age to the ac­cel­er­a­tor) and ul­ti­mately dam­age to the col­li­ma­tors them­selves. De­tailed steps and pa­ra­me­ters have been de­vel­oped and val­i­dated dur­ing two ded­i­cated ex­per­i­ments with beam in the LHC. This paper sum­ma­rizes the key as­pects in view of the prepa­ra­tion of such a pro­ce­dure for op­er­a­tional use, which will allow for the safe dis­posal of the full LHC beam by the op­er­a­tion crews. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF060  
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MOPMF061 Emittance Growth in Coast in the SPS at CERN emittance, cavity, scattering, feedback 257
 
  • F. Antoniou, H. Bartosik, T. Bohl, R. Calaga, L.R. Carver, J. Repond, G. Vandoni
    CERN, Geneva, Switzerland
  • A. Alekou
    UMAN, Manchester, United Kingdom
  
  Funding: Research supported by the HL-LHC project.
The HL-LHC pro­to­type crab-cav­i­ties are in­stalled in the CERN SPS, which will allow for a com­pre­hen­sive beam test with high en­ergy pro­tons for the first time. As the time avail­able for ex­per­i­men­tal beam dy­nam­ics stud­ies with the crab cav­i­ties in­stalled in the ma­chine will be lim­ited, a very good prepa­ra­tion is re­quired. One of the main con­cerns is the in­duced emit­tance growth, dri­ven by phase am­pli­tude jit­ter in the crab cav­i­ties. In this re­spect, sev­eral ma­chine de­vel­op­ment (MD) stud­ies were per­formed dur­ing the past years to quan­tify and char­ac­ter­ize the long term emit­tance evo­lu­tion of pro­ton beams in the SPS. In these pro­ceed­ings, the ex­per­i­men­tal ob­ser­va­tions from past years are sum­ma­rized and the MD stud­ies from 2016 and 2017 are pre­sented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF061  
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MOPMF069 The High Energy LHC Beam-Beam Effects studies octupole, beam-beam-effects, collider, dynamic-aperture 285
 
  • T. Pieloni, J. Barranco García, L. Rivkin, C. Tambasco
    EPFL, Lausanne, Switzerland
  • D. Amorim, S. A. Antipov, X. Buffat, B. Salvant, F. Zimmermann
    CERN, Geneva, Switzerland
  
  Funding: This work is supported by the Swiss State Secretariat for Education, Research and Innovation SERI.
We pre­sent in this paper the stud­ies of beam-beam ef­fects for the High En­ergy Large Hadron Col­lider. We will de­scribe and re­view the dif­fer­ent as­pects of beam-beam in­ter­ac­tions (i.e. orbit ef­fects, Lan­dau damp­ing, com­pen­sa­tion schemes and op­er­a­tional set-up). An op­er­a­tional sce­nario for the col­lider will also be given as a re­sult of the study. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF069  
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MOPMF086 Proposal of an Experimental Test at DAΦNE for the Low Emittance Muon Beam Production From Positrons on Target target, positron, emittance, optics 326
 
  • M. Boscolo, M. Antonelli, O.R. Blanco-García, S. Guiducci, A. Stella
    INFN/LNF, Frascati (Roma), Italy
  • F. Collamati
    INFN-Roma1, Rome, Italy
  • R. Li Voti
    Sapienza University of Rome, Rome, Italy
  • S.M. Liuzzo, P. Raimondi
    ESRF, Grenoble, France
  
  We pre­sent in this paper the pro­posal of an ex­per­i­men­tal test at DAΦNE of the positron-ring-plus-tar­get scheme fore­seen in the Low EMit­tance Muon Ac­cel­er­a­tor. This test would be a val­i­da­tion of the on-go­ing stud­ies for LEMMA and it would be syn­er­gic with other pro­pos­als at DAΦNE after the SID­DHARTA run. We dis­cuss the beam dy­nam­ics stud­ies for dif­fer­ent tar­gets in­serted in a proper lo­ca­tion through the ring, i.e. where the beam is fo­cused and dis­per­sion-free. Op­ti­miza­tion of beam pa­ra­me­ters, thick­ness and ma­te­r­ial of tar­get and op­tics of the tar­get in­ser­tion are shown as well. The de­vel­op­ment of the ex­is­tent di­ag­nos­tic needed to test the be­hav­ior of the cir­cu­lat­ing beam is de­scribed to­gether with the turn-by-turn mea­sure­ment sys­tems of charge, life­time and trans­verse size. Mea­sure­ments on the tem­per­a­ture and thermo-me­chan­i­cal stress on the tar­get are also under study.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF086  
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MOPMF088 Preparation Activity for the Siddharta-2 Run at DAΦNE luminosity, controls, feedback, quadrupole 334
 
  • C. Milardi, D. Alesini, S. Bini, O.R. Blanco-García, M. Boscolo, B. Buonomo, S. Cantarella, S. Caschera, A. D'Uffizi, A. De Santis, G.O. Delle Monache, D.G.C. Di Giulio, G. Di Pirro, A. Drago, L.G. Foggetta, A. Gallo, R. Gargana, A. Ghigo, S. Guiducci, S. Incremona, F. Iungo, C. Ligi, M. Maestri, A. Michelotti, L. Pellegrino, R. Ricci, U. Rotundo, L. Sabbatini, C. Sanelli, G. Sensolini, A. Stecchi, A. Stella, A. Vannozzi, M. Zobov
    INFN/LNF, Frascati (Roma), Italy
  • G. Castorina
    INFN-Roma1, Rome, Italy
  • J. Chavanne, G. Le Bec, P. Raimondi
    ESRF, Grenoble, France
  
  DAΦNE, the Fras­cati lep­ton col­lider work­ing at the c.m. en­ergy of the F res­o­nance, con­tin­ues to be a very suit­able in­fra­struc­ture to re­al­ize ex­per­i­ments aimed at study­ing el­e­men­tary par­ti­cles and nu­clear physics. The mo­ti­va­tions of this long last­ing in­ter­est are re­lated to the DAΦNE abil­ity of in­creas­ing its per­for­mances in terms of lu­mi­nos­ity thanks to the in­no­v­a­tive Crab-Waist col­li­sion scheme. In this frame­work, a new run for the SID­DHARTA-2 ex­per­i­ment has been planned in the year 2019. The de­tec­tor presently in­stalled in the in­ter­ac­tion re­gion, KLOE-2, will be re­moved and a new low-beta ses­sion, equipped with new per­ma­nent mag­nets quadrupoles, will be in­stalled. Di­ag­nos­tics tools will be im­proved es­pe­cially the ones used to keep under con­trol the beam-beam in­ter­ac­tion. The hor­i­zon­tal feed­back in the positron ring will be po­ten­ti­ated in order to achieve a higher positron cur­rent. The de­sign and de­vel­op­ment work done in view of the SID­DHARTA-2 run is pre­sented and dis­cussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF088  
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MOPMF089 DAΦNE Luminosity Monitor luminosity, detector, scattering, injection 338
 
  • A. De Santis, C. Bisegni, O.R. Blanco-García, O. Coiro, A. Michelotti, C. Milardi, A. Stecchi
    INFN/LNF, Frascati (Roma), Italy
  
  This work pre­sents a new method to mea­sure the DAΦNE col­lider in­stan­ta­neous lu­mi­nos­ity. The method is based on the iden­ti­fi­ca­tion of Bhabha scat­ter­ing events at low polar angle (∼10 de­gree) around the beam axis by using two small crys­tal calorime­ters shared with the KLOE-2 ex­per­i­ment. A new ex­per­i­men­tal setup has been de­signed and re­al­ized in order to im­ple­ment the fast lu­mi­nos­ity mon­i­tor, also in view of the DAΦNE fu­ture physics runs. Be­sides total in­stan­ta­neous lu­mi­nos­ity the new di­ag­nos­tic mea­sures also Bunch-by-Bunch (BBB) lu­mi­nos­ity. This pe­cu­liar­ity al­lows to in­ves­ti­gate the beam-beam in­ter­ac­tion for the Crab- Waist col­li­sions at DAΦNE and lu­mi­nos­ity de­pen­dence on the bunch train struc­ture.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF089  
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MOPMK014 Resistive-Wall Impedance of Insertions for FCC-hh impedance, insertion, optics, lattice 378
 
  • B. Riemann, S. Khan
    DELTA, Dortmund, Germany
  • S. Arsenyev, D. Schulte
    CERN, Geneva, Switzerland
  
  Funding: This work is supported by the German Ministry of Education & Research (BMBF, funding code 05P15PERB1) and CERN (reference numbers KE3123, EDMS 1606722).
In this work, trans­verse and lon­gi­tu­di­nal re­sis­tive-wall im­ped­ances for beam pipes in the ex­per­i­ment, in­jec­tion, ex­trac­tion and RF sys­tems in­ser­tion re­gions of the Fu­ture Hadron-Hadron Col­lider (FCC-hh) are com­puted based on con­tri­bu­tions from dif­fer­ent given cross sec­tions of the sur­round­ing (el­lip­ti­cal) cham­ber parts along the beam path, their tem­per­a­ture-de­pen­dent con­duc­tiv­i­ties, and op­ti­cal func­tions. An em­pha­sis is placed on the be­hav­iour of trans­verse im­ped­ance in the main ex­per­i­men­tal re­gions (A and G), where max­i­mum beta val­ues of 104 to 105 m occur in de­pen­dence of the op­er­a­tion mode re­spec­tively lat­tice con­fig­u­ra­tion. Main con­tri­bu­tions to the trans­verse and lon­gi­tu­di­nal im­ped­ance bud­get are iden­ti­fied, and pos­si­bil­i­ties of re­duc­ing them are dis­cussed. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMK014  
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MOPMK017 Transient Beam Loading Due to the Bunch Train Gap and Its Compensation Experiments at BEPC-II and ALS cavity, feedback, beam-loading, luminosity 390
 
  • H. Wang, R.A. Rimmer, S. Wang
    JLab, Newport News, Virginia, USA
  • J.P. Dai, Q. Qin, J. Xing, J.H. Yue, Y. Zhang
    IHEP, Beijing, People's Republic of China
  • D. Teytelman
    Dimtel, San Jose, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Non-uni­form bunch fill pat­terns in stor­age rings, dri­ven by the need to pro­vide gaps for beam abort­ing and ion clear­ing cause a large beam load­ing change in the RF cav­i­ties. The in­duced turn-pe­ri­odic tran­sient in the cav­ity volt­age mod­u­lates lon­gi­tu­di­nal beam prop­er­ties along the train, such as syn­chro­nous po­si­tion and bunch length. In the EIC de­sign, due to the asym­met­ric bunch train struc­ture be­tween the elec­tron and the ion beam, such mod­u­la­tion re­sults in shift­ing col­li­sion point and leads to re­duced lu­mi­nos­ity. We have car­ried out the beam based ex­per­i­ments at BEPC-II and ALS using bunch-by-bunch di­ag­nos­tic ca­pa­bil­i­ties of the cou­pled-bunch feed­back sys­tems to study this tran­sient ef­fect. A mod­u­lated bunch fill­ing pat­tern with higher charge den­sity around the gap has been demon­strated to be ef­fec­tive in par­tially com­pen­sat­ing this tran­sient mod­u­la­tion. De­tails of the ex­per­i­men­tal se­tups and the data analy­sis will be pre­sented to this con­fer­ence. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMK017  
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MOPML011 Liquid Cluster Ion Beam Processing of Transition Metal Films vacuum, acceleration, radiation, target 415
 
  • D. Shimizu, H. Ryuto, M. Takeuchi, D. Yamamoto
    Kyoto University, Photonics and Electronics Science and Engineering Center, Kyoto, Japan
  
  The ir­ra­di­a­tion ef­fects of clus­ter ion beams are char­ac­ter­ized by the high-den­sity col­li­sion of mol­e­cules that com­prise the clus­ters against a tar­get. Ac­cord­ing to mol­e­c­u­lar dy­nam­ics cal­cu­la­tions, the local tem­per­a­ture of the col­lid­ing clus­ter and the sur­face of the tar­get are ex­pected to in­crease to sev­eral thou­sand K. The en­hance­ment of the chem­i­cal in­ter­ac­tions be­tween the mol­e­cules in the col­lid­ing clus­ters and the atoms on the tar­get sur­face is ex­pected, if poly­atomic mol­e­cules, such as ethanol and ace­tone, are used for the source ma­te­r­ial of the clus­ter. So, the ir­ra­di­a­tion ef­fects of the poly­atomic liq­uid clus­ter ion beams on tran­si­tion metal films have been stud­ied to ex­am­ine the pos­si­bil­ity of uti­liz­ing the liq­uid clus­ter ion beam tech­nique for the pro­cess­ing of tran­si­tion metal films. The tran­si­tion metal films were formed by mag­netron sput­ter­ing. The liq­uid clus­ters were pro­duced by the adi­a­batic ex­pan­sion method and ion­ized by elec­tron ion­iza­tion. The sput­ter­ing yields of tran­si­tion metal films in­duced by liq­uid clus­ter ions are dis­cussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML011  
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MOPML012 Special Collimation System Configuration for the LHC High-Beta Runs background, collimation, simulation, detector 418
 
  • H. Garcia Morales
    Royal Holloway, University of London, Surrey, United Kingdom
  • R. Bruce, H. Burkhardt, M. Deile, S. Jakobsen, A. Mereghetti, S. Redaelli
    CERN, Geneva, Switzerland
  
  Spe­cial LHC high-beta op­tics is re­quired for the for­ward physics pro­gram of TOTEM and AT­LAS-ALFA. In this con­fig­u­ra­tion, the beam is de-squeezed (the \beta-func­tion at the col­li­sion point is in­creased) in order to min­i­mize the di­ver­gence for mea­sure­ments at very small scat­ter­ing an­gles. In these low beam in­ten­sity runs, it is im­por­tant to place the Roman Pots (RPs) as close as pos­si­ble to the beam, which de­mands spe­cial col­li­ma­tor set­tings. Dur­ing Run I, a sig­nif­i­cant amount of back­ground was ob­served in the for­ward de­tec­tors due to par­ti­cles outscat­tered from the pri­mary col­li­ma­tor. Dur­ing Run II, a dif­fer­ent col­li­ma­tion con­fig­u­ra­tion was used where a tung­sten col­li­ma­tor was used as pri­mary col­li­ma­tor in­stead of the usual one made of car­bon. Using this con­fig­u­ra­tion, a sig­nif­i­cant re­duc­tion of the back­ground at the RPs was ob­served. In this paper we pre­sent a de­scrip­tion of the new col­li­ma­tor con­fig­u­ra­tion and the re­sults ob­tained dur­ing the high-beta run car­ried out in 2016.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML012  
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MOPML023 Very-High Energy Electron (VHEE) Studies at CERN's CLEAR User Facility simulation, electron, scattering, proton 445
 
  • A. Lagzda, R.M. Jones
    UMAN, Manchester, United Kingdom
  • A. Aitkenhead, K. Kirkby, R. MacKay, M. Van Herk
    The Christie NHS Foundation Trust, Manchester, United Kingdom
  • R. Corsini, W. Farabolini
    CERN, Geneva, Switzerland
  
  Funding: Science and Technology Facilities Council (STFC) - United Kingdom
Here we in­ves­ti­gate how in­serts of var­i­ous den­si­ties (0.001-2.2 g/cm3) af­fect the dose dis­tri­b­u­tion prop­er­ties of VHEE beams at ~150 MeV. A range vari­a­tion com­par­i­son was also made with clin­i­cal pro­ton beams using TOPAS/GEANT4 Monte Carlo sim­u­la­tions. In ad­di­tion, we as­sess the vi­a­bil­ity of scat­ter­ing foils for op­ti­miz­ing the size of VHEE beams for ra­dio­ther­apy pur­poses. The ex­per­i­ments were con­ducted at CERN's CLEAR user fa­cil­ity. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML023  
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MOPML028 Accelerator Machines and Experimental Activities in the ENEA Frascati Particle Accelerators and Medical Application Laboratory radiation, proton, electron, linac 460
 
  • M. Vadrucci, A. Ampollini, G. Bazzano, F. Borgognoni, P. Nenzi, L. Picardi, C. Ronsivalle, V. Surrenti, E. Trinca
    ENEA C.R. Frascati, Frascati (Roma), Italy
  
  Funding: Regione Lazio - TOP IMPLART Project
In the ENEA Fras­cati re­search cen­ter the APAM (Par­ti­cle Ac­cel­er­a­tors and Med­ical Ap­pli­ca­tion) lab­o­ra­tory is de­voted to the de­vel­op­ment of par­ti­cle ac­cel­er­a­tors for med­ical ap­pli­ca­tions. Two main fa­cil­i­ties are op­er­a­tional. The TOP-IM­PLART pro­ton ac­cel­er­a­tor is a pulsed fully lin­ear ma­chine aimed at ac­tive in­ten­sity mod­u­lated pro­ton ther­apy with a final en­ergy of 150 MeV. The ma­chine of­fers two beam ex­trac­tion points: one at 3-7 MeV, on a ver­ti­cal line, and the other one at 35 MeV, the max­i­mum en­ergy cur­rently avail­able, with a pulse cur­rent up to 35 μA, on the hor­i­zon­tal line. The REX (Re­mov­able tar­get Elec­tron X-ray) source con­sists of an elec­tron stand­ing wave LINAC gen­er­at­ing a beam in the en­ergy range of 3 to 5 MeV with a pulsed cur­rent of 0.2 A. This source can gen­er­ate Bremsstrahlung X-ray beams using suit­able con­vert­ers (Pb, W, Ta). This paper de­scribes the ex­per­i­men­tal re­sults of satel­lite ac­tiv­i­ties per­formed in these fa­cil­i­ties in the fields of bi­ol­ogy, dosime­try, elec­tron­ics, PIXE spec­troscopy and preser­va­tion of cul­tural her­itage man­u­facts. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML028  
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MOPML030 Demonstration of a Tunable Electron Beam Chopper for Application in 200 kV stroboscopic TEM electron, kicker, laser, controls 467
 
  • C.-J. Jing, S.V. Baryshev, A. Kanareykin, A. Liu, Y. Zhao
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • J.W. Lau
    NIST, Gaithersburg, Maryland, USA
  • D. Masiel, B. Reed
    Integrated Dynamic Electron Solutions, Pleasanton, California, USA
  • Y. Zhu
    BNL, Upton, Long Island, New York, USA
  
  Funding: The project is supported by the Office of Basic Energy Science of DOE through a Small Business Innovative Research grant #DE-SC0013121.
For the last sev­eral decades, time-re­solved trans­mis­sion elec­tron mi­cro­scopes (TEM) ex­plor­ing the sub-mi­crosec­ond timescale have re­lied on the pho­toe­mis­sion tech­nol­ogy to gen­er­ate the sin­gle or train of elec­tron bunches. How­ever, the com­plex­ity of ad­di­tional laser sys­tem and the avail­abil­ity of high repi­ti­tion rate laser limit ap­pli­ca­tions of the laser-dri­ven ap­proach. Lately we have made sub­stan­tial progress to­wards pi­o­neer­ing a new kind of time-re­solved TEM, com­ple­men­tary to the ex­ist­ing laser-based tech­niques. Using a tun­able RF beam-chop­per, we are able to retro­fit an exsit­ing TEM pro­vid­ing a pulsed elec­tron beam at a con­tin­u­ously tun­able rep­ti­tion rate up to 12GHz and a tun­able bunch length. In the ar­ti­cle we will briefly dis­cuss the work­ing prin­ci­ple and ex­per­i­men­tal progress to date. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML030  
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MOPML032 Prospects for a Muon Spin Resonace Facility in the Fermilab MuCool Test Area target, linac, timing, resonance 474
 
  • J.A. Johnstone, C. Johnstone
    Fermilab, Batavia, Illinois, USA
  
  Funding: Work supported by Fermi Reserach Alliance, LLC under Contract no. DE-AC02-07CH11359 with the United States Department of Energy.
This paper in­ves­ti­gates the fea­si­bil­ity of re-pur­pos­ing the Mu­Cool Test Area beam­line and ex­per­i­men­tal hall to sup­port a Muon Spin Res­o­nance Fa­cil­ity which would make it the only such fa­cil­ity in the US. This re­port re­views the basic muon pro­duc­tion con­cepts as stud­ied and op­er­a­tionally im­ple­mented at TRI­UMF, PSI, and RAL and their ap­pli­ca­tion in the con­text of the MTA fa­cil­ity. Two sce­nar­ios were de­ter­mined fea­si­ble. One, an ini­tial min­i­mal-shield­ing and cap­i­tal-cost in­vest­ment stage with a sin­gle sec­ondary muon beam­line that uti­lizes an ex­ist­ing pri­mary beam ab­sorber and, an­other, an up­graded stage, that im­ple­ments an op­ti­mized pro­duc­tion tar­get, a prox­i­mate high-in­ten­sity ab­sorber, and op­ti­mized sec­ondary muon lines. A unique ap­proach is pro­posed which chops or strips a macropulse of H− beam into a mi­cropulse sub­struc­ture - a muon cre­ation tim­ing scheme - which al­lows Muon Spin Res­o­nance ex­per­i­ments in a linac en­vi­ron­ment. With this tim­ing scheme, and at­ten­tion to tar­get de­sign and sec­ondary beam col­lec­tion, the MTA can host en­abling and com­pet­i­tive Muon Spin Res­o­nance ex­per­i­ments. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML032  
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MOPML045 Measurement of Displacement Cross-Section for Structural Materials in High-Power Proton Accelerator Facility proton, target, radiation, cryogenics 499
 
  • S.I. Meigo, S.H. Hasegawa, H.I. Hiroki, H. Hiroki, Y. Iwamoto, F.M. Maekawa
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • T. Ishida, S. Makimura, T. Nakamoto
    KEK, Ibaraki, Japan
  • Y. Makoto
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  
  As the in­crease of beam power of hadron ac­cel­er­a­tors, the dam­age to tar­get ma­te­r­ial is es­sen­tial. For es­ti­ma­tion of dam­age such as tar­get ma­te­r­ial used at the fa­cil­ity, dis­place­ment per atom (DPA), cal­cu­lated by the par­ti­cle flux mul­ti­plied dis­place­ment cross-sec­tion with cas­cade mode, is widely em­ployed as an index of the dam­age. Al­though the DPA is em­ployed as the stan­dard, the ex­per­i­men­tal data of dis­place­ment cross-sec­tion are scarce for a pro­ton in the en­ergy re­gion above 20 MeV. A re­cent study re­ports that the dis­place­ment cross sec­tion of tung­sten has 8 times dif­fer­ence among the cal­cu­la­tion mod­els. There­fore, ex­per­i­men­tal data of the dis­place­ment cross-sec­tion is cru­cial. The dis­place­ment cross-sec­tion can be ob­tained by ob­serv­ing the change of re­sis­tiv­ity of the sam­ple cooled by GM cooler to sus­tain the dam­age. The sam­ple is placed in the vac­uum cham­ber placed at up­stream of the beam dump for 3 GeV and 30 GeV syn­chro­trons in J-PARC, where the sam­ple will be ir­ra­di­ated by the pro­ton in the en­ergy range be­tween 0.4 and 30 GeV. In the vast en­ergy range, the dis­place­ment cross-sec­tion can be ob­tained for the pro­ton, which will help to im­prove the dam­age es­ti­ma­tion of the tar­get ma­te­r­ial.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML045  
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MOPML049 Generation of 1-MeV Quasi-Monochromatic Gamma-Rays for Precise Measurement of Delbrück Scattering by Laser Compton Scattering laser, scattering, electron, photon 508
 
  • H. Zen, T. Kii, H. Ohgaki
    Kyoto University, Kyoto, Japan
  • M. Fujimoto, M. Katoh, E. Salehi
    UVSOR, Okazaki, Japan
  • T. Hayakawa, T. Shizuma
    QST, Tokai, Japan
  • M. Katoh
    Sokendai - Okazaki, Okazaki, Aichi, Japan
  • J. Koga
    National Institutes for Quantum and Radiological Science and Technology, Kyoto, Japan
  • E. Salehi
    AUT, Tehran, Iran
  
  Delbrück scat­ter­ing is the elas­tic scat­ter­ing of pho­tons by the elec­tro­mag­netic field of an atomic nu­cleus, as a con­se­quence of vac­uum po­lar­iza­tion. The iso­lated mea­sure­ment of Delbrück scat­ter­ing has not been per­formed be­cause of in­ter­fer­ence with other elas­tic scat­ter­ing processes. It was re­cently dis­cov­ered that, using lin­early po­lar­ized pho­tons, Delbrück scat­ter­ing can be mea­sured nearly in­de­pen­dently of the other scat­ter­ing processes*. In order to per­form a proof of prin­ci­ple ex­per­i­ment, a quasi-mono­chro­matic gamma-ray beam with a max­i­mum pho­ton en­ergy of 1 MeV has been gen­er­ated at the UVSOR fa­cil­ity by col­lid­ing a CO2 laser with a 750-MeV elec­tron beam. A pre­lim­i­nary ex­per­i­ment has been per­formed with 0.5-W laser power and 1-mA elec­tron beam cur­rent. As a re­sult, the mea­sured gamma-ray flux was eval­u­ated as 0.0006 pho­ton/eV/mA/W/s around the peak en­ergy of 1 MeV. If we ac­cept 20 per­cent en­ergy spread, in case of a 100-W CO2 laser col­lid­ing with a 300 mA elec­tron beam, ap­prox­i­mately 4 x 106-pho­tons/s gamma-rays could be ob­tained. This flux is suf­fi­ciently high for the proof of prin­ci­ple ex­per­i­ment.
*J.K. Koga and T. Hayakawa, Phys. Rev. Lett. 118, 204801 (2017). 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML049  
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MOPML051 First Performance Calculations for the Very High Energy Electron Radiation Therapy Experiment at PRAE radiation, electron, proton, photon 516
 
  • A. Faus-Golfe
    LAL, Orsay, France
  • R. Delorme, Y. Prezado
    IMNC, Orsay, France
  • V. Favaudon, C. Fouillade, S. Heinrich, A. Mazal, A. Patriarca, P. Poortmans, P. Verrelle
    Institut Curie - Centre de Protonthérapie d'Orsay, Orsay, France
  • A. Hrybok
    National Taras Shevchenko University of Kyiv, Radiophysical Faculty, Kiev, Ukraine
  
  The Plat­form for Re­search and Ap­pli­ca­tions with Elec­trons (PRAE) pro­ject aims at cre­at­ing a mul­ti­dis­ci­pli­nary R&D plat­form at the Orsay cam­pus, join­ing var­i­ous sci­en­tific com­mu­ni­ties in­volved in ra­dio­bi­ol­ogy, sub­atomic physics, in­stru­men­ta­tion, par­ti­cle ac­cel­er­a­tors and clin­i­cal re­search around a high-per­for­mance elec­tron ac­cel­er­a­tor with beam en­er­gies up to 70 MeV and later 140 MeV, in order to per­form a se­ries of unique mea­sure­ments and chal­leng­ing R&D. In this paper we will re­port the first op­tics de­sign and per­for­mance eval­u­a­tions of such a mul­ti­dis­ci­pli­nary ma­chine, fo­cus­ing on Very High En­ergy Elec­trons (VHEE) in­no­v­a­tive Ra­di­a­tion Ther­apy (RT) ap­pli­ca­tions in par­tic­u­lar by al­low­ing Grid and FLASH method­olo­gies, which are likely to rep­re­sent a major break­through in RT. Func­tional spec­i­fi­ca­tions in­clude beam in­ten­si­ties to pro­duce dose rates from 2 Gy/min to 100Gy/sec, beam sizes with di­am­e­ters from 0.5 mm to 10 cm or more of ho­mo­ge­neous beams and mon­i­tor­ing de­vices with ac­cu­racy in the order of 1-2% for sin­gle or mul­ti­ple beams and sin­gle or mul­ti­ple frac­tions in bi­o­log­i­cal and ppre­clin­i­cal ap­pli­ca­tions. High en­er­gies (>140 MeV) would be also needed for GRID ther­apy.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML051  
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MOPML056 Evidence of the Electron-Screened Oppenheimer Philips Reactions 162Er(d, n)163Tm or 162Er(p,γ)163Tm in Deuterated Materials Subjected to a Low-Energy Photon Beam electron, neutron, proton, target 533
 
  • T.L. Benyo, A. Chait, L.P. Forsley, M. Pines, V. Pines, B.M. Steinetz
    NASA Glenn Research Center, Cleveland, USA
  
  NASA GRC has in­ves­ti­gated elec­tron-screen­ing of deuter­ated met­als using MV elec­tron lin­ear ac­cel­er­a­tors (LINACs). GRC found that re­peat­able sub-thresh­old nu­clear re­ac­tions may have oc­curred re­sult­ing in nu­clear prod­ucts ob­served via wit­ness-ma­te­r­ial neu­tron ac­ti­va­tion using high pu­rity ger­ma­nium (HPGe) gamma spec­troscopy and liq­uid scin­til­la­tor spec­troscopy. The sus­pected path of cre­ation may be the re­sult of elec­tron-screened Op­pen­heimer-Phillips re­ac­tions or Mir­ror Op­pen­heimer-Phillips re­ac­tions. Ev­i­dence of 162Er(d, n)163Tm or 162Er(p,γ)163Tm has been shown with the ap­pear­ance of gamma peaks co­in­cid­ing with 163Tm with a pub­lished ' life of 22 min­utes from sam­ples con­tain­ing deuter­ated er­bium ex­posed to a pho­ton beam. Both of these re­ac­tions are a vari­a­tion of the Op­pen­heimer-Phillips nu­clear re­ac­tion. Ev­i­dence of the re­ac­tions have been de­tected by an HPGe gamma de­tec­tion sys­tem and wit­nessed within gamma spec­tra col­lected from deuter­ated ma­te­ri­als sub­jected to a nom­i­nally 1.95 MeV pho­ton beam. This paper de­scribes the the­ory be­hind the pro­posed re­ac­tions, the ex­per­i­ments con­ducted at GRC, and the ex­per­i­men­tal ev­i­dence of the sus­pected cre­ation of the 163Tm iso­tope.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML056  
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MOPML062 Accelerator Neutron Source for Boron Neutron Capture Therapy neutron, vacuum, proton, tandem-accelerator 550
 
  • S.Yu. Taskaev, D.A. Kasatov, A.N. Makarov, Y.M. Ostreinov, I.M. Shchudlo, I.N. Sorokin
    BINP SB RAS, Novosibirsk, Russia
  • T.A. Bykov
    Budker INP & NSU, Novosibirsk, Russia
  • Ya.A. Kolesnikov, A.M. Koshkarev, E.O. Sokolova
    NSU, Novosibirsk, Russia
  
  Funding: This study was carried out with a grant from the Russian Science Foundation (project No. 14-32-00006-P) with the support of the Budker Institute of Nuclear Physics and Novosibirsk State University.
A source of ep­ither­mal neu­trons based on a vac­uum-in­su­lated tan­dem ac­cel­er­a­tor and a lithium tar­get is de­vel­oped for the tech­nique of boron neu­tron cap­ture ther­apy. A sta­tion­ary pro­ton beam of 2 MeV with a cur­rent of up to 5 mA was ob­tained in the ac­cel­er­a­tor. Neu­tron gen­er­a­tion was per­formed and the flux and neu­tron spec­trum were ex­per­i­men­tally mea­sured. A Beam Shap­ing As­sem­bly was de­vel­oped and man­u­fac­tured, which makes it pos­si­ble to form a ther­a­peu­tic beam of neu­trons to the great­est ex­tent sat­is­fy­ing the re­quire­ments of BNCT. It was es­tab­lished that neu­tron ir­ra­di­a­tion of tumor cells of human glioma U251 and human glioblas­toma T98G, pre­vi­ously in­cu­bated in a medium with boron, led to a sig­nif­i­cant sup­pres­sion of their vi­a­bil­ity. Ir­ra­di­a­tion of mice with grafted human glioblas­toma tumor led to their com­plete cure. In order to in­crease the beam pa­ra­me­ters, the fa­cil­ity was equipped with a wire scan­ner OWS-30 (D-Pace, Canada; under the li­cense of TRI­UMF), a non-con­tact cur­rent sen­sor NPTC (Ber­gos, France), a FLIR T650SC in­frared cam­era, an Op­tris CT Laser 3ML SF py­rom­e­ter (Op­tris, GmbH, Ger­many), cooled di­aphragms with ther­mis­tors, tele­scopic beam re­ceivers with ther­more­sis­tors, a new bush­ing in­su­la­tor. Two new sources of neg­a­tive hy­dro­gen ions with a high cur­rent are being pre­pared, one of them is sur­face-plasma, the other is vo­lu­mi­nous. The in­ves­ti­ga­tions es­tab­lished the ef­fect of space charge and spher­i­cal aber­ra­tion of lens on the ion beam trans­port, the de­pen­dence of the heat­ing of the di­aphragms of the elec­trodes and the size of the pro­ton beam on the cur­rent of the in­jected beam of neg­a­tive hy­dro­gen ions and the pres­sure of the resid­ual gas in the trans­port chan­nel. The re­port de­scribes the mod­ern­iza­tion of the ac­cel­er­a­tor, dis­cusses the re­sults of re­search, de­clares plans. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML062  
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MOPML063 In Situ Observations of Blistering of a Metal Irradiated with 2 MeV Protons proton, neutron, radiation, target 553
 
  • S.Yu. Taskaev, D.A. Kasatov, A.N. Makarov, I.M. Shchudlo
    BINP SB RAS, Novosibirsk, Russia
  • A. Badrutdinov, Y. Higashi, T. Miyazawa
    OIST, Onna-son, Okinawa, Japan
  • T.A. Bykov
    Budker INP & NSU, Novosibirsk, Russia
  • S.A. Gromilov
    Nikolaev IIC, Novosibirsk, Russia
  • Ya.A. Kolesnikov, A.M. Koshkarev, E.O. Sokolova
    NSU, Novosibirsk, Russia
  • H. Sugawara
    KEK, Ibaraki, Japan
  
  Funding: This study was carried out with a grant from the Russian Science Foundation (project No. 14-32-00006-P) with the support of the Budker Institute of Nuclear Physics and Novosibirsk State University.
A vac­uum-in­su­lated tan­dem ac­cel­er­a­tor was used to ob­serve in situ blis­ter­ing dur­ing 2-MeV pro­ton ir­ra­di­a­tion of metal­lic sam­ples to a flu­ence of up to 6.7 1020 cm2. Sam­ples con­sist­ing of cop­per of dif­fer­ent pu­rity, tan­ta­lum, and tan­ta­lum-cop­per com­pounds were placed on the pro­ton beam path and forced to cool. The sur­face state of the sam­ples was ob­served using a CCD cam­era with a re­mote mi­cro­scope. Ther­mis­tors, a py­rom­e­ter, and an in­frared cam­era were ap­plied to mea­sure the tem­per­a­ture of the sam­ples dur­ing ir­ra­di­a­tion. After ir­ra­di­a­tion, the sam­ples were an­a­lyzed on an X-ray dif­frac­tome­ter, laser and elec­tron mi­cro­scopes. The pre­sent study de­scribes the ex­per­i­ment, pre­sents the re­sults ob­tained and notes their rel­e­vance and sig­nif­i­cance in the de­vel­op­ment of a lithium tar­get for an ac­cel­er­a­tor-based neu­tron source, for use in boron neu­tron cap­ture ther­apy of can­cer. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML063  
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MOPML066 Ultrafast Mega-electron-volt Gas-Phase Electron Diffraction at SLAC National Accelerator Laboratory electron, gun, vacuum, laser 556
 
  • X. Shen, R.K. Li, X.J. Wang, S.P. Weathersby, J. Yang
    SLAC, Menlo Park, California, USA
  
  Funding: This work was supported in part by the U.S. Department of Energy Contract No. DE-AC02-76SF00515, and the SLAC UED/UEM Initiative Program Development Fund.
Ul­tra­short mega-elec­tron-volt (MeV) elec­tron beams from ra­dio-fre­quency (rf) pho­toin­jec­tors have re­cently at­tracted strong in­ter­ests for ap­pli­ca­tion in ul­tra­fast gas-phase elec­tron dif­frac­tion (UGED). Such high-bright­ness elec­tron beams are ca­pa­ble of pro­vid­ing 100-fs level tem­po­ral res­o­lu­tion and sub-Angstrom level spa­tial res­o­lu­tion to cap­ture the ul­tra­fast struc­tural dy­nam­ics from pho­toex­cited gas mol­e­cules. To ex­per­i­men­tally demon­strate such an ul­tra­fast elec­tron scat­ter­ing in­stru­ment, a high per­for­mance UGED sys­tem has been com­mis­sioned at SLAC Na­tional Ac­cel­er­a­tor Lab­o­ra­tory. The UGED in­stru­ment pro­duces 3.7 MeV elec­tron beams with 2 fC beam charge at 180-Hz rep­e­ti­tion rate. The tem­po­ral res­o­lu­tion is char­ac­ter­ized to be 150 fs full-width-at-half-max­i­mum (FWHM), while the spa­tial res­o­lu­tion is mea­sured to be 0.76 Å FWHM. The UGED in­stru­ment also demon­strates out­stand­ing per­for­mance in vac­uum, rf, and elec­tron beam point­ing sta­bil­ity. De­tails of the per­for­mance of the SLAC MeV UGED sys­tem is re­ported in this paper. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML066  
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TUXGBD2 Colliding Heavy Ions in the LHC luminosity, heavy-ion, operation, proton 584
 
  • J.M. Jowett
    CERN, Geneva, Switzerland
  
  The Large Hadron Col­lider at CERN not only col­lides pro­tons but also heav­ier nu­clei. So far Pb+Pb, Xe-Xe and p+Pb col­li­sions, at mul­ti­ple en­er­gies, have been pro­vided for what was ini­tially con­ceived as a dis­tinct physics pro­gram on the col­lec­tive be­hav­ior of QCD mat­ter at ex­treme en­ergy den­sity and tem­per­a­ture. How­ever un­ex­pected phe­nom­ena ob­served in p+Pb and p+p col­li­sions at equiv­a­lent en­er­gies have blurred the dis­tinc­tion. In­tense, low-emit­tance, ion beams are pro­vided by a ded­i­cated source and in­jec­tor chain setup. When Pb beams col­lide, new lu­mi­nos­ity lim­its arise from pho­ton-pho­ton and pho­tonu­clear in­ter­ac­tions but ef­fec­tive mit­i­ga­tions have al­lowed lu­mi­nosi­ties over 3 times de­sign. Asym­met­ric p+Pb col­li­sions in­tro­duce new fea­tures and beam-dy­nam­i­cal phe­nom­ena into op­er­a­tion of the LHC but have also achieved lu­mi­nos­ity far be­yond ex­pec­ta­tions. With ex­per­i­men­tal re­quire­ments for mul­ti­ple changes in en­ergy and data-tak­ing con­fig­u­ra­tions dur­ing very short heavy-ion runs, high op­er­a­tional ef­fi­ciency and re­li­a­bil­ity are vital. This in­vited talk dis­cusses per­for­mance, fu­ture prospects, and tech­ni­cal chal­lenges for the LHC heavy ion pro­gram, in­clud­ing in­jec­tor per­for­mance.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUXGBD2  
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TUXGBE1 Status and Prospects for the AWAKE Experiment electron, plasma, proton, wakefield 595
 
  • M. Turner
    CERN, Geneva, Switzerland
  
  The AWAKE Col­lab­o­ra­tion is pur­su­ing a demon­stra­tion of pro­ton-dri­ven plasma wake­field ac­cel­er­a­tion of elec­trons. The AWAKE ex­per­i­ment uses a §I{400}{GeV/c} pro­ton bunch from the CERN SPS, with a rms bunch length of 6-§I{15}{cm}, to drive wake­fields in a §I10{m} long ru­bid­ium plasma with an elec­tron den­sity of 1014-1015cm-3. Since the drive bunch length is much longer than the plasma wave­length (λpe<§I{3}{mm}) for these plasma den­si­ties, AWAKE per­formed ex­per­i­ments to prove that the long pro­ton bunch self-mod­u­lates in the plasma (2017). The next step is to demon­strate ac­cel­er­a­tion of elec­trons in the wake­fields dri­ven by the self-mod­u­lated bunch (2018). We sum­ma­rize the con­cept of the self-mod­u­la­tion mea­sure­ments and de­scribe the plans and chal­lenges for the elec­tron ac­cel­er­a­tion ex­per­i­ments.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUXGBE1  
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TUXGBE2 Study of Ultra-High Gradient Acceleration in Carbon Nanotube Arrays plasma, electron, acceleration, wakefield 599
 
  • J. Resta-López, A.S. Alexandrova, V. Rodin, Y. Wei, C.P. Welsch, G.X. Xia
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • Y. M. Li, Y. Zhao
    UMAN, Manchester, United Kingdom
  
  Solid-state based wake­field ac­cel­er­a­tion of charged par­ti­cles was pre­vi­ously pro­posed to ob­tain ex­tremely high gra­di­ents on the order of 1 − 10 TeV/m. In re­cent years the pos­si­bil­ity of using ei­ther metal­lic or car­bon nan­otube struc­tures is at­tract­ing new at­ten­tion. The use of car­bon nan­otubes would allow us to ac­cel­er­ate and chan­nel par­ti­cles over­com­ing many of the lim­i­ta­tions of using nat­ural crys­tals, e.g. chan­nel­ing aper­ture re­stric­tions and ther­mal-me­chan­i­cal ro­bust­ness is­sues. In this paper, we pro­pose a po­ten­tial proof of con­cept ex­per­i­ment using car­bon nan­otube ar­rays, as­sum­ing the beam pa­ra­me­ters and con­di­tions of ac­cel­er­a­tor fa­cil­i­ties al­ready avail­able, such as CLEAR at CERN and CLARA at Dares­bury. The ac­cel­er­a­tion per­for­mance of car­bon nan­otube ar­rays is in­ves­ti­gated by using a 2D Par­ti­cle-In-Cell (PIC) model based on a multi-hol­low plasma. Op­ti­mum ex­per­i­men­tal beam pa­ra­me­ters and sys­tem lay­out are dis­cussed.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUXGBE2  
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TUXGBE3 Status of Plasma-Based Experiments at the SPARC_LAB Test Facility plasma, electron, focusing, emittance 603
 
  • E. Chiadroni, D. Alesini, M.P. Anania, M. Bellaveglia, A. Biagioni, F.G. Bisesto, E. Brentegani, F. Cardelli, G. Costa, M. Croia, D. Di Giovenale, G. Di Pirro, M. Ferrario, F. Filippi, A. Gallo, A. Giribono, A. Marocchino, L. Piersanti, R. Pompili, S. Romeo, J. Scifo, V. Shpakov, A. Stella, C. Vaccarezza, F. Villa
    INFN/LNF, Frascati (Roma), Italy
  • A. Cianchi
    INFN-Roma II, Roma, Italy
  • M. Marongiu, A. Mostacci
    Sapienza University of Rome, Rome, Italy
  • J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • A.R. Rossi
    Istituto Nazionale di Fisica Nucleare, Milano, Italy
  • A. Zigler
    The Hebrew University of Jerusalem, The Racah Institute of Physics, Jerusalem, Israel
  
  The cur­rent ac­tiv­ity of the SPARC LAB test-fa­cil­ity is fo­cused on the re­al­iza­tion of plasma-based ac­cel­er­a­tion ex­per­i­ments with the aim to pro­vide ac­cel­er­at­ing field of the order of sev­eral GV/m while main­tain­ing the over­all qual­ity (in terms of en­ergy spread and emit­tance) of the ac­cel­er­ated elec­tron bunch. The cur­rent sta­tus of such an ac­tiv­ity is pre­sented, to­gether with re­sults re­lated to the ap­plic­a­bil­ity of plas­mas as fo­cus­ing lenses in view of a com­plete plasma-based fo­cus­ing, ac­cel­er­at­ing and ex­trac­tion sys­tem.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUXGBE3  
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TUYGBE3 Recent progress of short pulse dielectric two-beam acceleration acceleration, linear-collider, collider, wakefield 640
 
  • J.H. Shao, M.E. Conde, D.S. Doran, W. Gai, W. Liu, N.R. Neveu, J.F. Power, C. Whiteford, E.E. Wisniewski, L.M. Zheng
    ANL, Argonne, Illinois, USA
  • C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio, USA
  
  Two-Beam Ac­cel­er­a­tion (TBA) is a struc­ture-based wake­field ac­cel­er­a­tion method with the po­ten­tial to meet the lu­mi­nos­ity and cost re­quire­ments of a TeV class lin­ear col­lider. The Ar­gonne Wake­field Ac­cel­er­a­tor (AWA) fa­cil­ity is de­vel­op­ing a di­elec­tric-based short pulse TBA scheme with the po­ten­tial to with­stand high ac­cel­er­a­tion gra­di­ents and to achieve low fab­ri­ca­tion cost. Re­cently, the di­elec­tric short pulse TBA tech­nol­ogy was suc­cess­fully demon­strated using K-band 26 GHz struc­tures, achiev­ing 55 MW out­put power from the power ex­trac­tor and 28 MeV/m gra­di­ent in the ac­cel­er­a­tor. To im­prove the gen­er­ated rf power, an X-band 11.7 GHz power ex­trac­tor has been de­vel­oped, which ob­tained 105 MW in the high power test. In ad­di­tion, a novel di­elec­tric disk ac­cel­er­a­tor (DDA) is cur­rently under in­ves­ti­ga­tion to sig­nif­i­cantly in­crease the ef­fi­ciency of lin­ear col­lid­ers based on short pulse TBA. De­tails of these re­search will be pre­sented in this paper.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUYGBE3  
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TUPAF023 The Beamlines of the CERN East Area Renovation Project target, secondary-beams, radiation, operation 717
 
  • J. Bernhard, M. Bonnet, Q. Bouirek, D. Brethoux, B.D. Carlsen, A. Ebn Rahmoun, J. Etheridge, S. Evrard, L. Gatignon, E. Harrouch, M. Lazzaroni, M. Van Dijk, A. Watrigant
    CERN, Geneva, Switzerland
  
  The East Area at the Pro­ton Syn­chro­tron is one of CERN's longest run­ning fa­cil­i­ties for ex­per­i­ments, beam tests, and ir­ra­di­a­tions with a suc­cess­ful his­tory of over 55 years. The fa­cil­ity serves more than 20 user teams for about 200 days of run­ning each year and of­fers mixed sec­ondary hadron, elec­tron and muon beams of 0.5 GeV/c to 10 GeV/c. In ad­di­tion, the pri­mary pro­ton beam or ion beam is trans­ported to the ir­ra­di­a­tion fa­cil­i­ties CHARM and IRRAD. Due to the steadily high user de­mand, the CERN man­age­ment ap­proved an up­grade and ren­o­va­tion of the fa­cil­ity to meet fu­ture beam test and physics re­quire­ments. New beam op­tics will as­sure a bet­ter trans­mis­sion and pu­rity of the sec­ondary beams, now also with the pos­si­bil­ity of highly pure elec­tron, hadron or muon beams. The up­grade in­cludes a pulsed pow­er­ing scheme with en­ergy re­cov­er­ing power sup­plies and new mag­nets, re­duc­ing both power and cool­ing re­quire­ments. To­gether with the build­ing con­sol­i­da­tion, this re­sults in a con­sid­er­ably lower en­ergy con­sump­tion. The ren­o­va­tion phase is sched­uled dur­ing the tech­ni­cal stops be­tween 2018 and 2020. We will give an overview of the pro­ject scope in­clud­ing up­grades and fu­ture beams.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF023  
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TUPAF025 Multi-turn Study in FLUKA for the Design of CERN-PS Internal Beam Dumps dumping, simulation, operation, proton 724
 
  • J.A. Briz Monago, M. Calviani, F. Cerutti, J.J. Esala, S.S. Gilardoni, F.-X. Nuiry, G. Romagnoli, G. Sterbini, V. Vlachoudis
    CERN, Geneva, Switzerland
  
  The CERN Pro­ton-Syn­chro­tron (PS) ac­cel­er­a­tor is cur­rently equipped with two in­ter­nal beam dumps in op­er­a­tion since the 1970's. An up­grade is re­quired to be able to with­stand the beams that will be pro­duced after the end of the LIU (LHC In­jec­tor Up­grade) pro­ject. For the de­sign of the new dumps, the in­ter­ac­tion and trans­port of beam and all sec­ondary par­ti­cles gen­er­ated has been sim­u­lated using FLUKA. The work­ing prin­ci­ple of the in­ter­nal beam dump in the PS ring is very pe­cu­liar with re­spect to the other dumps in the CERN ac­cel­er­a­tor com­plex. A mov­ing dump in­ter­cepts the cir­cu­lat­ing beam dur­ing few mil­lisec­onds like a fast scraper. The mov­ing dump shav­ing the beam, the multi-turn trans­port of beam par­ti­cles in the PS ac­cel­er­a­tor and a time-de­pen­dent en­ergy de­po­si­tion in the dump were mod­eled. The method­ol­ogy and the re­sults ob­tained in our stud­ies for the dump core and down­stream equip­ment will be re­ported in this con­tri­bu­tion.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF025  
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TUPAF032 Beam Transfer Line Design to the SPS Beam Dump Facility target, proton, extraction, quadrupole 751
 
  • Y. Dutheil, J. Bauche, M. Calviani, L.A. Dougherty, M.A. Fraser, B. Goddard, C. Heßler, J. Kurdej, E. Lopez Sola
    CERN, Geneva, Switzerland
  
  Stud­ies for the SPS Beam Dump Fa­cil­ity (BDF) are on­go­ing within the scope of the Physics Be­yond Col­lider pro­ject. The BDF is a pro­posed fixed tar­get fa­cil­ity to be in­stalled in the SPS North Area, to ac­com­mo­date the SHiP ex­per­i­ment (Search for Hid­den Par­ti­cles), which is most no­tably aim­ing at study­ing hid­den sec­tor par­ti­cles. This ex­per­i­ment re­quires a high in­ten­sity slowly ex­tracted 400 GeV pro­ton beam with 4·1013 pro­tons per 1 s spill to achieve 4·1019 pro­tons on tar­get per year. The ex­trac­tion and trans­port scheme will make use of the first 600 m of the ex­ist­ing North Area ex­trac­tion line. In this paper, we will pre­sent the de­sign of the ad­di­tional 600 m of trans­fer line to­wards BDF branch­ing off from the ex­ist­ing line and dis­cuss the de­tailed de­sign of the BDF beam line, its com­po­nents and op­tics. We pre­sent the lat­est re­sults on the study and de­sign of a new lam­i­nated Lam­bert­son split­ter mag­net to pro­vide fast switch be­tween the cur­rent North Area ex­per­i­ments and the BDF. The lat­est spec­i­fi­ca­tion of a di­pole di­lu­tion sys­tem used to re­duce the local peak power of the beam on the tar­get is also pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF032  
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TUPAF035 Observations of SPS Slow-Extracted Spill Quality Degradation and Possible Improvements extraction, quadrupole, power-supply, simulation 761
 
  • F.M. Velotti, H. Bartosik, K. Cornelis, M.A. Fraser, B. Goddard, S. Hirlaender, V. Kain, O. Michels, M. Pari
    CERN, Geneva, Switzerland
  
  The SPS de­liv­ers slow ex­tracted pro­ton and heavy ion spills of sev­eral sec­onds to the North Area fixed tar­get ex­per­i­ments with a very high duty fac­tor. Re­duced ma­chine re­pro­ducibil­ity due to mag­netic his­tory and power sup­ply rip­ples on the main cir­cuits lead how­ever to fre­quent degra­da­tion of the spill duty fac­tor. In this paper, the mea­sured ef­fect of the SPS mag­netic his­tory on spill qual­ity and prin­ci­pal ma­chine pa­ra­me­ters is pre­sented. An­other de­tailed mea­sure­ment cam­paign was aimed at char­ac­ter­is­ing the fre­quency con­tent and re­sponse of the spill to noise on the main power sup­plies rip­ples. The main find­ings of this study will also be re­ported. Fi­nally, sim­u­la­tions of pos­si­ble im­prove­ments based on the data ac­quired are dis­cussed, as well as an ex­trap­o­la­tion to the pos­si­ble spill qual­ity after the im­ple­men­ta­tion of the im­prove­ments.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF035  
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TUPAF038 Prototyping Activities for a New Design of CERN's Antiproton Production Target target, proton, antiproton, operation 772
 
  • C. Torregrosa, M.E.J. Butcher, M. Calviani, J.P.C. Espadanal, R. Ferriere, L. Gentini, E. Grenier-Boley, L. Mircea Grec, A. Perillo-Marcone, R. Seidenbinder, N.S. Solieri, M.A. Timmins, E. Urrutia, V. Vlachoudis
    CERN, Geneva, Switzerland
  
  An­tipro­tons are pro­duced at CERN by im­pact­ing in­tense pro­ton beams of 26 GeV/c onto a high-Z wa­ter-cooled tar­get. The cur­rent de­sign con­sists in an Ir core tar­get in a graphite ma­trix and in­serted in a Ti-6Al-4V as­sem­bly. A new tar­get de­sign has been fore­seen for op­er­a­tion after 2021 aim­ing at im­prov­ing the op­er­a­tion ro­bust­ness and an­tipro­ton pro­duc­tion yield, trig­ger­ing sev­eral R&D ac­tiv­i­ties dur­ing the last years. First, both nu­mer­i­cal (use of hy­drocodes) and ex­per­i­men­tal ap­proaches were car­ried out to study the core ma­te­r­ial re­sponse under ex­treme dy­namic load­ing when im­pacted by the pri­mary pro­ton beam. The lessons learnt from these stud­ies have been then ap­plied to fur­ther pro­to­typ­ing and test­ing under pro­ton beam im­pact at the CERN-Hi­Rad­Mat fa­cil­ity. A first scaled pro­to­type con­sist­ing in Ta rods em­bed­ded in an ex­panded graphite ma­trix was ir­ra­di­ated in 2017, while in 2018, the PRO­TAD ex­per­i­ment will test dif­fer­ent real-scale AD-Tar­get pro­to­types, in which the old wa­ter-cooled as­sem­bly is re­placed by a more com­pact air-cooled one, and dif­fer­ent core geom­e­try and ma­te­r­ial con­fig­u­ra­tions are in­ves­ti­gated. This con­tri­bu­tion de­tails these pro­to­typ­ing and test­ing ac­tiv­i­ties.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF038  
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TUPAF039 Electron Cooling Simulation and Experimental Benchmarks at LEIR electron, plasma, simulation, solenoid 776
 
  • A. Latina, H. Bartosik, N. Biancacci, R. Corsini, D. Gamba, S. Hirlaender, A. Huschauer
    CERN, Geneva, Switzerland
  
  A fast and ac­cu­rate sim­u­la­tion of Elec­tron Cool­ing has re­cently been im­ple­mented in the track­ing code RF-Track. The im­ple­men­ta­tion, which is based on a "hy­brid ki­netic" model, en­ables the sim­u­la­tion of a large va­ri­ety of re­al­is­tic sce­nar­ios, in­clud­ing im­per­fec­tions such as gra­di­ents in the elec­tron den­sity, mis­align­ments of elec­trons / ions / so­le­noidal fields, both in the sta­tic and in the dy­namic regimes. Bench­marks of the sim­u­la­tions against mea­sure­ments per­formed at LEIR, using Lead and Xenon ions, are pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF039  
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TUPAF041 Residual Gas Ions Characterization from the REXEBIS detector, ISOL, rfq, electron 784
 
  • N. Bidault, M.L. Lozano, J.A. Rodriguez
    CERN, Geneva, Switzerland
  
  The Iso­tope mass Sep­a­ra­tor On-Line DE­vice (ISOLDE) is a user fa­cil­ity lo­cated at CERN where Ra­dioac­tive Ion Beams (RIBs) are pro­duced from pro­ton col­li­sions onto a tar­get, mass sep­a­rated and trans­ported to user ex­per­i­men­tal sta­tions ei­ther di­rectly at low en­ergy or after being post- ac­cel­er­ated, no­tably for nu­clear physics stud­ies. Prior to ac­cel­er­a­tion through the REX/HIE-ISOLDE lin­ear ac­celer- ator, the ion beam is ac­cu­mu­lated, bunched and cooled in a Pen­ning trap (REX­TRAP) and af­ter­wards charge-bred in an Elec­tron Beam Ion Source (REXE­BIS). Multi-charged ra­dioac­tive species of in­ter­est are then se­lected by a mass-to- charge (A/q) ratio sep­a­ra­tor di­pole in the Low En­ergy Beam Trans­fer Line (LEBT). A method is pre­sented to char­ac­ter- ize the Resid­ual Gas Ion (RGI) back­ground con­t­a­m­i­na­tion for different op­er­a­tional con­di­tions of the REXE­BIS. More par­tic­u­larly, a dis­cus­sion is held about the influence of the confine­ment time in­side the charge-breeder on the resid­ual gas spec­trum. Fi­nally, a method to iden­tify sub-pico-Am­pere con­t­a­m­i­nants is demon­strated.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF041  
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TUPAF042 Characterization of the Beam Energy Spread at the REX/HIE-ISOLDE Linac cavity, ISOL, linac, detector 787
 
  • M.L. Lozano, N. Bidault, E. Fadakis, M.A. Fraser, E. Matli, J.A. Rodriguez
    CERN, Geneva, Switzerland
  
  ISOLDE is an on-line ra­dioac­tive iso­tope sep­a­ra­tor lo­cated at CERN that works by col­lid­ing pro­tons ac­cel­er­ated in the PS Booster into a fixed tar­get and by sep­a­rat­ing the re­sul­tant ion­ized iso­topes using a mag­netic sep­a­ra­tor. The com­ple­tion of the HIE-ISOLDE su­per­con­duct­ing linac al­lows the ac­cel­er­a­tion of these ions to en­ergy lev­els that were not reach­able be­fore, open­ing the door to new ex­per­i­ments in dif­fer­ent fields. These ex­per­i­ments often have spe­cial re­quire­ments in terms of beam in­ten­sity and pu­rity, trans­verse emit­tance or en­ergy spread. A pos­si­ble way to re­duce the en­ergy spread of the beam de­liv­ered to the ex­per­i­men­tal sta­tions is to use one or more of the su­per­con­duct­ing cav­i­ties as bunch­ers. The main re­sults of sev­eral tests con­ducted dur­ing the last beam com­mis­sion­ing cam­paign prove that this mode of op­er­a­tion is fea­si­ble and will be pre­sented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF042  
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TUPAF043 Testing the Double-Crystal Setup for Physics Beyond Colliders Experiments in the UA9-SPS Experiment proton, detector, collimation, target 790
 
  • S. Montesano
    CERN, Geneva, Switzerland
  
  Funding: on behalf of the UA9 Collaboration
The UA9 ex­per­i­ment is in­stalled in the CERN SPS to study how co­her­ent in­ter­ac­tion in crys­talline ma­te­ri­als can be used to steer par­ti­cles beams. Re­cently, new ex­per­i­ments re­quir­ing com­plex beam ma­nip­u­la­tions by means of crys­tals have been pro­posed in the frame­work of the Physics Be­yond Col­lid­ers study group at CERN. In par­tic­u­lar, it was pro­posed to use a first crys­tal to di­rect pro­tons from the LHC beam halo on a tar­get placed in the beam pipe and to use a sec­ond crys­tal to de­flect the par­ti­cles pro­duced in the tar­get (dou­ble-crys­tal setup), al­low­ing to mea­sure their po­lar­iza­tion. The lay­out of the UA9 ex­per­i­ment in the CERN SPS has been mod­i­fied to study the fea­si­bil­ity of the pro­posed sce­nario and its com­pat­i­bil­ity with the del­i­cate en­vi­ron­ment of a su­per­con­duct­ing col­lider. A first set of mea­sure­ments was per­formed in 2017 prov­ing that the pro­tons de­flected by the first crys­tal can be in­ter­cepted and suc­cess­fully de­flected by a sec­ond crys­tal. A fur­ther up­grade of the ex­per­i­ment in 2018 will allow mea­sur­ing more pre­cisely the com­bined ef­fi­ciency of the two crys­tals and the beam-in­duced back­ground. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF043  
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TUPAF045 Studies for Future Fixed-Target Experiments at the LHC in the Framework of the CERN Physics Beyond Colliders Study target, collider, proton, luminosity 798
 
  • S. Redaelli, M. Ferro-Luzzi
    CERN, Geneva, Switzerland
  • C. Hadjidakis
    IN2P3-CNRS, Orsay, France
  
  A study on prospects for Physics Be­yond Col­lid­ers at CERN was launched in Sep­tem­ber 2016 to as­sess the ca­pa­bil­i­ties of the ex­ist­ing ac­cel­er­a­tors com­plex. Among sev­eral other work­ing groups, this ini­tia­tive trig­gered the cre­ation of a work­ing group with the scope of study­ing a few spe­cific pro­pos­als to per­form fixed-tar­get physics ex­per­i­ments at the Large Hadron Col­lider (LHC). This in­cludes for ex­am­ple physics ex­per­i­ments with solid or gaseous in­ter­nal tar­gets, po­lar­ized gas tar­gets, and ex­per­i­ments using bent-crys­tals for halo split­ting from beam core for in­ter­nal tar­gets. The focus of the work­ing group's ac­tiv­i­ties is on the tech­ni­cal fea­si­bil­ity and on im­pli­ca­tions to the LHC ring. In this paper, the cur­rent sta­tus of the stud­ies is pre­sented and fu­ture plans are dis­cussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF045  
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TUPAF050 Beam Dynamics Simulations of the Effect of Power Converter Ripple on Slow Extraction at the CERN SPS extraction, quadrupole, emittance, sextupole 818
 
  • J. Prieto, M.A. Fraser, B. Goddard, V. Kain, L.S. Stoel, F.M. Velotti
    CERN, Geneva, Switzerland
  
  The SPS pro­vides slowly ex­tracted pro­tons at 400 GeV/c to CERN's North Area Fixed Tar­get ex­per­i­ments over spills of du­ra­tion from 1-10 sec­onds. Low fre­quency rip­ple on the cur­rent in the main mag­nets orig­i­nat­ing from their power con­vert­ers is a com­mon issue that de­grades the slow-ex­tracted spill qual­ity. In order to bet­ter un­der­stand how the sta­bil­ity of the power con­vert­ers af­fects losses, beam emit­tance and spill qual­ity, par­ti­cle track­ing sim­u­la­tions were car­ried out using MAD-X and com­pared to mea­sure­ments, with the im­pact of each mag­net cir­cuit in­ves­ti­gated sys­tem­at­i­cally. The im­pli­ca­tions for the per­for­mance of the SPS slow ex­trac­tion are dis­cussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF050  
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TUPAF060 Injection and Dump Systems for a 13.5 TeV Hadron Synchrotron HE-LHC kicker, injection, extraction, septum 858
 
  • W. Bartmann, M.J. Barnes, L. Ducimetière, B. Goddard, M. Hofer, T. Kramer, A. Lechner, E. Renner, A. Sanz Ull, V. Senaj, L.S. Stoel, C. Wiesner
    CERN, Geneva, Switzerland
  
  One op­tion for a fu­ture cir­cu­lar col­lider at CERN is to build a 13.5 TeV hadron syn­chro­tron, or High En­ergy LHC (HE-LHC) in the LHC tun­nel. In­jec­tion and dump sys­tems will have to be up­graded to cope with the higher beam rigid­ity and in­creased dam­age po­ten­tial of the beam. The re­quired mod­i­fi­ca­tions of the beam trans­fer hard­ware are high­lighted in view of tech­nol­ogy ad­vance­ments in the field of kicker switch tech­nol­ogy. An op­ti­mised straight sec­tion op­tics is shown.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF060  
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TUPAF078 Recent Results of HESR Original Stochastic Cooling Tanks at COSY kicker, pick-up, storage-ring, hardware 913
 
  • R. Stassen, B. Breitkreutz, N. Shurkhno
    FZJ, Jülich, Germany
  
  The High En­ergy Stor­age Ring (HESR) of the FAIR pro­ject at GSI Darm­stadt will be very im­por­tant for dif­fer­ent sci­en­tific pro­grams due to the mod­u­lar­ized start ver­sion of FAIR. Sto­chas­tic cool­ing to­gether with bar­rier bucket op­er­a­tion will be the key com­po­nent to ful­fill the re­quire­ments of the dif­fer­ent ex­per­i­ments. First pickup and first kicker of the HESR sto­chas­tic cool­ing sys­tem have been in­stalled into the COSY ac­cel­er­a­tor at FZJ Jülich. COSY is well suited to test the per­for­mance of the HESR sto­chas­tic cool­ing hard­ware at dif­fer­ent en­er­gies and vari­able par­ti­cle num­bers. The novel ded­i­cated HESR-struc­tures were al­ready suc­cess­fully tested at the Nu­clotron in Dubna for lon­gi­tu­di­nal cool­ing and dur­ing a beam time 2017 for trans­verse cool­ing at COSY. The re­sults of the last sto­chas­tic cool­ing beam time will be pre­sented as well as the first use of GaN based am­pli­fiers in a sto­chas­tic cool­ing sys­tem. The HESR needs fast trans­mis­sion-lines be­tween PU and KI. Be­side air-filled coax-lines, op­ti­cal hol­low fiber-lines are very at­trac­tive. First re­sults with such a hol­low fiber used for the trans­verse sig­nal path will be pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF078  
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TUPAF081 Measurements and Simulations of the Spill Quality of Slowly Extracted Beams from the SIS-18 Synchrotron sextupole, extraction, synchrotron, resonance 924
 
  • S. Sorge, P. Forck, R. Singh
    GSI, Darmstadt, Germany
  
  In this con­tri­bu­tion, re­sults of re­cent mea­sure­ments of the spill struc­ture of slowly ex­tracted beams out of the GSI heavy ion syn­chro­tron SIS-18 are pre­sented and com­pared to re­sults of sim­u­la­tions. Aim of the study is the de­ter­mi­na­tion of spill struc­tures at sev­eral kHz which arise from rip­ples in the fields of the ac­cel­er­a­tor mag­nets due to im­per­fec­tions of the mag­nets' power sup­plies. The goal of the study is to un­der­stand how the rip­ple is trans­ferred from the mag­nets to the spill and to find pos­si­ble ways for spill smooth­ing. For this pur­pose a com­pre­hen­sive sim­u­la­tion model for slow ex­trac­tion is in prepa­ra­tion which will be val­i­dated with beam-based mea­sure­ments.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF081  
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TUPAF083 SIS100 Tunnel Design and Civil Construction Status site, status, radiation, shielding 927
 
  • C. Omet, J. Falenski, H. Kisker, K. Konradt, P.J. Spiller
    GSI, Darmstadt, Germany
  • A. Fischer
    FAIR, Darmstadt, Germany
  
  As the FAIR Pro­ject is pro­ceed­ing, build­ing de­signs have been frozen and the ac­cord­ing work pack­ages ten­dered. For the fu­ture FAIR main dri­ver ac­cel­er­a­tor, SIS100, the 1.1 km long ac­cel­er­a­tor tun­nel "T110", has been planned 17 m deep under ground. In this ar­ti­cle, en­vi­ron­men­tal bound­ary con­di­tions, the cho­sen lay­out and the cur­rent sta­tus of civil con­struc­tion is pre­sented.  
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TUPAK005 Upgrade Plan of J-PARC MR - Toward 1.3 MW Beam Power operation, injection, proton, cavity 966
 
  • T. Koseki
    KEK, Ibaraki, Japan
  
  The Main Ring Syn­chro­tron (MR), a 30-GeV slow cy­cling pro­ton syn­chro­tron, de­liv­ers in­tense pro­ton beam to a long-base­line neu­trino os­cil­la­tion ex­per­i­ment, T2K, by fast ex­trac­tion and to an ex­per­i­men­tal fa­cil­ity, which is called hadron hall by slow ex­trac­tion. The achieved beam in­ten­si­ties for rou­tine op­er­a­tions are 470 kW ( 2.4 x 1014 ppp) for the fast ex­trac­tion and 44 kW ( 5.1 x 1013 ppp) for the slow ex­trac­tion. In order to in­crease the beam in­ten­sity, a plan to re­place the mag­net power sup­plies are now in progress for op­er­a­tion with a higher rep­e­ti­tion rate. After the re­place­ment, the cycle time will be short­ened about a half and in­crease beam in­ten­si­ties two times larger for the fast ex­trac­tion. In ad­di­tion, a fur­ther up­grade plan for the fast ex­trac­tion is mainly re­in­force­ment of rf power sup­plies. The goal of the up­grade plan is reach­ing 1.3 MW beam power for the neu­trino ex­per­i­ment.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAK005  
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TUPAK007 Simulation of Surface Muon Beamline, Ultra-Slow Muon Production and Extraction for the J-PARC g-2/EDM Experiment simulation, target, laser, proton 970
 
  • M. Otani, N. Kawamura, T. Mibe, T. Yamazaki
    KEK, Tsukuba, Japan
  • K. Ishida
    RIKEN Nishina Center, Wako, Japan
  • G. Marshall
    TRIUMF, Vancouver, Canada
  
  The E34 ex­per­i­ment aims to mea­sure muon anom­alous mag­netic mo­ment with a pre­ci­sion of 0.1 ppm to cast light on be­yond stan­dard model in el­e­men­tary par­ti­cle physics. The ex­per­i­ment uti­lizes a brand new muon beam line in J-PARC (H line), which is de­signed to have large ac­cep­tance to sup­ply an in­tense muon beam. The sur­face muons are in­jected into a sil­ica aero­gel tar­get to gen­er­ate bound state of muon and elec­tron (muo­nium). Then the muo­ni­ums are ion­ized by lasers and ultra slow (30 meV) muons (USM) are gen­er­ated. The USM's are ex­tracted by elec­tro-sta­tic lens and in­jected to a muon linac. In this poster, sim­u­la­tion for op­tics of the sur­face muon beam­line, muo­nium pro­duc­tion and ex­trac­tion by the elec­tro-sta­tic lens, and the es­ti­ma­tion of the USM's in­ten­sity are pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAK007  
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TUPAK009 Muon Profile Measurement After Acceleration With a Radio-Frequency Quadrupole Linac simulation, rfq, linac, positron 977
 
  • M. Otani, Y. Fukao, K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, T. Yamazaki
    KEK, Tsukuba, Japan
  • S. Bae, H. Choi, S. Choi, B. Kim, H.S. Ko
    SNU, Seoul, Republic of Korea
  • K. Hasegawa, Y. Kondo, T. Morishita
    JAEA/J-PARC, Tokai-mura, Japan
  • T. Iijima, Y. Sue
    Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
  • H. Iinuma, Y. Nakazawa
    Ibaraki University, Ibaraki, Japan
  • K. Ishida
    RIKEN Nishina Center, Wako, Japan
  • R. Kitamura
    University of Tokyo, Tokyo, Japan
  • S. Li
    The University of Tokyo, Graduate School of Science, Tokyo, Japan
  • G.P. Razuvaev
    Budker INP & NSU, Novosibirsk, Russia
  • N. Saito
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • E. Won
    Korea University, Seoul, Republic of Korea
  
  Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP16H03987, and JP16J07784.
The E34 ex­per­i­ment aims to mea­sure muon anom­alous mag­netic mo­ment with a pre­ci­sion of 0.1ppm. The ex­per­i­ment uti­lizes low emit­tance muon beam with a muon linac to sweep out beam re­lated un­cer­tain­ties, which limit the g-2 pre­ci­sion in past ex­per­i­ments. A beam match­ing with pre­cise beam mea­sure­ments is re­quired to avoid sub­stan­tial emit­tance growth and sat­isfy the ex­per­i­men­tal re­quire­ment on the beam emit­tance of around 1.5 pi mm mrad. We con­duct pro­file mea­sure­ment of muon after ac­cel­er­a­tion with a ra­dio-fre­quency quadru­pole (RFQ) on De­cem­ber 2017 fol­low­ing a first muon ac­cel­er­a­tion ex­per­i­ment on Oc­to­ber. In the ex­per­i­ment of pro­file mea­sure­ment, epi-ther­mal neg­a­tive muo­nium ions are gen­er­ated by in­ject­ing sur­face muons to a thin metal foil. The muo­nium ions are ac­cel­er­ated to 5 keV. by an elec­tro-sta­tic lens and ac­cel­er­ated to 90 keV by the RFQ. Then the muo­nium ions are trans­ported to a pro­file de­tec­tor con­sist­ing of a mi­cro-chan­nel plate and a ccd cam­era via a quadru­pole pair and a bend­ing mag­net. In this poster, the ex­per­i­men­tal re­sult and com­par­i­son to the sim­u­la­tion are re­ported. 		 
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TUPAK016 Commissioning of the Diagnostic Beam Line for the Muon RF Acceleration with H− Ion Beam Derived from the Ultraviolet Light acceleration, quadrupole, diagnostics, MMI 997
 
  • Y. Nakazawa, H. Iinuma
    Ibaraki University, Ibaraki, Japan
  • N. Kawamura, T. Mibe, M. Otani, T. Yamazaki
    KEK, Ibaraki, Japan
  • R. Kitamura
    University of Tokyo, Tokyo, Japan
  • Y. Kondo
    JAEA/J-PARC, Tokai-mura, Japan
  • N. Saito
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • Y. Sue
    Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
  
  Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP16H03987, and JP16J07784.
A muon LINAC is under de­vel­op­ment for a pre­cise mea­sure­ment of muon g-2 / EDM at J-PARC. We con­ducted an ex­per­i­ment of a muon RF ac­cel­er­a­tion on Oc­to­ber and De­cem­ber 2017. The sur­face muon beam is ir­ra­di­ated to a metal de­grader to gen­er­ate slow neg­a­tive muo­nium. The slow neg­a­tive muo­ni­ums are ac­cel­er­ated to 90 keV with an elec­tro­sta­tic ac­cel­er­a­tor and an RFQ. Prior to muon RF ac­cel­er­a­tion, we con­ducted a com­mis­sion­ing of the di­ag­nos­tic beam line con­sist­ing of two quadru­pole mag­nets and a bend­ing mag­net. The ul­tra­vi­o­let light is ir­ra­di­ated to an alu­minum foil and H− ion is gen­er­ated. It sim­u­lates a neg­a­tive muo­nium and is ac­cel­er­ated with an elec­tro­sta­tic ac­cel­er­a­tor. This sys­tem al­lowed us to check op­er­a­tion for the di­ag­nos­tic beam line, which is es­sen­tial task for trans­porta­tion and mo­men­tum se­lec­tion of the neg­a­tive muo­nium. In this paper, I would like to re­port the per­for­mance eval­u­a­tion of the di­ag­nos­tic beam line by H− ions. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAK016  
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TUPAL002 Numerical Calibration of the Injection Bump Sizes During the Beam Commissioning for CSNS injection, MMI, flattop, neutron 1011
 
  • M.Y. Huang, S. Wang, S.Y. Xu
    IHEP, Beijing, People's Republic of China
  
  In order to con­trol the strong space charge ef­fects, which cause large beam loss dur­ing the in­jec­tion and ac­cel­er­a­tion processes, phase space paint­ing method was used for in­ject­ing a small emit­tance beam from the linac into the large ac­cep­tance of the Rapid Cy­cling Syn­chro­tron (RCS). Dur­ing the beam com­mis­sion­ing, in order to con­trol and op­ti­mize the paint­ing re­sults, the po­si­tions and ranges of the hor­i­zon­tal and ver­ti­cal paint­ing should be ad­justed ac­cu­rately. There­fore, the nu­mer­i­cal cal­i­bra­tion of the in­jec­tion bump sizes was very im­por­tant and need to be done as soon as pos­si­ble. In this paper, a method to cal­i­brate the hor­i­zon­tal and ver­ti­cal bump sizes was pre­sented and ap­plied to China Spal­la­tion Neu­tron Source (CSNS). The nu­mer­i­cal cal­i­bra­tion re­sults would be given and dis­cussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL002  
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TUPAL021 Evaluation of Activated Nuclides Due to Secondary Particles Produced in Stripper Foil in J-PARC RCS proton, radiation, neutron, target 1048
 
  • M. Yoshimoto, S. Kato, M. Kinsho, K. Okabe, P.K. Saha, K. Yamamoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  
  Multi-turn charge-ex­change beam in­jec­tion is key tech­nique to achieve the high in­ten­sity pro­ton beam ac­cel­er­a­tors. In the J-PARC RCS, 400MeV H− beams from the LINAC are con­verted to H+ beam with the strip­per foils, and then in­jected into the ring. The strip­per foil is ir­ra­di­ated by not only the in­ject­ing H− beams but also the cir­cu­lat­ing H+ beams. The high en­ergy and high power beam ir­ra­di­a­tion into the foil in­duces the nu­clear re­ac­tions, and gen­er­ated sec­ondary neu­trons and pro­tons. These sec­ondary par­ti­cles causes high resid­ual does around the strip­per foil. Now, to iden­tify species of sec­ondary par­ti­cles and to iden­tify en­er­gies and emis­sion an­gles, ac­ti­va­tion analy­sis method using the sam­ple pieces is con­sid­ered. In this pre­sen­ta­tion, we re­port the re­sult of the eval­u­a­tion of this ac­ti­va­tion analy­sis with PHITS codes.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL021  
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TUPAL028 New Feature of the Oscillating Synchrotron Motion Derived from the Hamiltonian Composed of Three Motions synchrotron, betatron, closed-orbit, storage-ring 1060
 
  • K. Jimbo
    Kyoto University, Kyoto, Japan
  
  The equa­tion for the syn­chro­tron mo­tion was de­rived from the Hamil­ton­ian, which was com­posed of coast­ing, be­ta­tron and syn­chro­tron mo­tions*. The be­ta­tron os­cil­la­tion is　the hor­i­zon­tal os­cil­la­tion. The syn­chro­tron os­cil­la­tion is not only an os­cil­la­tion of the rev­o­lu­tion fre­quency but also an os­cil­la­tion of the av­er­age ra­dius. The syn­chro­tron os­cil­la­tion is both lon­gi­tu­di­nal and hor­i­zon­tal os­cil­la­tions and it is pos­si­ble to ex­change en­ergy with the be­ta­tron os­cil­la­tion. The syn­chro­tron os­cil­la­tion oc­curs under a con­stant par­ti­cle ve­loc­ity and the Hamil­ton­ian is con­served.
*K.Jimbo, Physical Review Special Topics - Accelerator and Beams 19, 010102 (2016). 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL028  
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TUPAL045 Towards Operational Scalability for H− Laser Assisted Charge Exchange laser, cavity, operation, radiation 1110
 
  • S.M. Cousineau, A.V. Aleksandrov, T.V. Gorlov, Y. Liu, M.A. Plum, A. Rakhman, A.P. Shishlo
    ORNL, Oak Ridge, Tennessee, USA
  • D.E. Johnson, S. Nagaitsev
    Fermilab, Batavia, Illinois, USA
  • M.J. Kay
    UTK, Knoxville, Tennessee, USA
  
  The ex­per­i­men­tal de­vel­op­ment of H− laser as­sisted charge ex­change, a.k.a. laser strip­ping, has been on­go­ing at the SNS ac­cel­er­a­tor since 2006 in a three-phase ap­proach. The first two phases as­so­ci­ated with proof-of-prin­ci­ple and proof-of-prac­ti­cal­ity ex­per­i­ments have been suc­cess­fully com­pleted and demon­strated >95% H− strip­ping ef­fi­ciency for up to 10 us. The final phase is a proof-of-scal­a­bil­ity stage to demon­strate that the method can be de­ployed for re­al­is­tic beam duty fac­tors. The ex­per­i­men­tal com­po­nent of this ef­fort is cen­tered on achiev­ing high ef­fi­ciency strip­ping through the use of a laser power am­pli­fi­ca­tion scheme to re­cy­cle the macropulse laser light at the in­ter­ac­tion point of the H− strip­ping. Such a re­cy­cling cav­ity will be nec­es­sary for any fu­ture op­er­a­tional laser strip­ping sys­tem with at least mil­lisec­ond du­ra­tion H− pulses. A sec­ond com­po­nent of the proof-of-scal­a­bil­ity phase is to de­velop a con­cep­tual de­sign for a re­al­is­tic laser strip­ping scheme. The sta­tus of these ef­forts and chal­lenges as­so­ci­ated with de­ploy­ing the re­cy­cling cav­ity into the laser strip­ping ex­per­i­ment will be de­scribed in this talk.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL045  
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TUPAL050 Progress Work on a CW Deuteron RFQ with Magnetic Coupling Windows rfq, cavity, coupling, Windows 1123
 
  • Q. Fu, M.J. Easton, P.P. Gan, S.L. Gao, H.P. Li, Y.R. Lu, Q.Y. Tan, Z. Wang, K. Zhu
    PKU, Beijing, People's Republic of China
  • W.P. Dou, Y. He
    IMP/CAS, Lanzhou, People's Republic of China
  
  Funding: This work was supported by the National Basic Research Program of China (Grant No. 2014CB845503).
A new 162.5 MHz RFQ has been built for a joint 973 pro­ject be­tween Peking Uni­ver­sity (PKU) and In­sti­tute of Mod­ern Physics (IMP). It is de­signed to de­liver 50-mA deuteron beams to 1 MeV in CW mode, with an in­ter-volt­age of 60 kV and a length of 1.809 m. Due to its win­dow-type struc­ture, the RFQ has com­pact cross-sec­tion, suf­fi­cient mode sep­a­ra­tion and high spe­cific shunt im­ped­ance. It con­sists of two seg­ments fab­ri­cated and in­stalled at IMP. The as­sem­bling error of the cav­ity is less than 0.05 mm. The RF mea­sure­ments show good elec­tri­cal prop­er­ties of the res­o­nant cav­ity with a mea­sured un­loaded qual­ity fac­tor equal to 96.4% of the sim­u­lated value. After tun­ing, we ob­tained the nom­i­nal fre­quency and field un­bal­ance within 1.0%. Prepa­ra­tion of high-power test of this RFQ is un­der­way. This paper will cover the fab­ri­ca­tion de­tails and RF mea­sure­ments, as well as the progress of high-power test. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL050  
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TUPAL054 Experimental Measurements of Resonances near to the ISIS Working Point resonance, synchrotron, controls, space-charge 1132
 
  • P.T. Griffin-Hicks, B. Jones, B.G. Pine, C.M. Warsop, M. Wright
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  
  ISIS is the pulsed spal­la­tion neu­tron source lo­cated at the Ruther­ford Ap­ple­ton Lab­o­ra­tory in the UK. Op­er­a­tion is based on a 50 Hz, 800 MeV pro­ton syn­chro­tron, ac­cel­er­at­ing up to 3·1013 pro­tons per pulse (ppp), which pro­vides beam to two tar­get sta­tions. ISIS is beam loss lim­ited, so to achieve greater beam in­ten­sity and op­ti­mal op­er­a­tion, losses must be re­duced. Some beam loss may be at­trib­uted to res­o­nance lines found in be­ta­tron tune space. These could be dri­ven by higher order mag­net field com­po­nents, er­rors or mis­align­ment. This paper de­scribes work mea­sur­ing losses against tune space around the ISIS work­ing point. Ex­per­i­ments have been car­ried out to mea­sure beam loss against tune in the ISIS syn­chro­tron. The ex­per­i­ments were done at low in­ten­sity to min­imise space charge and in­ten­sity ef­fects. Res­o­nance lines that cause beam loss can be clearly iden­ti­fied and pro­vide new in­for­ma­tion about the ma­chine. The ex­per­i­men­tal process has been au­to­mated in order to de­crease ex­per­i­ment du­ra­tion and to re­duce sys­tem­atic human error. MAD-X mod­els that com­pare the beam en­ve­lope at dif­fer­ent points in tune space to the beam pipe aper­ture are used to dis­tin­guish be­tween losses caused by in­creased en­ve­lope size and losses in­duced by dri­ven res­o­nances.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL054  
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TUPAL057 Preliminary Experiments in Caesium Delivery and Gettering on the ISIS Vespa Source ion-source, plasma, operation, site 1144
 
  • T. M. Sarmento, R.E. Abel, D.C. Faircloth, S.R. Lawrie, J.H. Macgregor, M. Whitehead, T. Wood
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  
  Cae­sium cap­ture by graphite at var­i­ous tem­per­a­tures 20- 300°C in the VESPA ion source test stand was ex­plored in a pre­lim­i­nary ex­per­i­ment. An ac­com­pa­ny­ing ex­per­i­ment was set up to eval­u­ate the con­trol of cae­sium boiler de­liv­ery in the var­i­ous ISIS pen­ning sources. Re­sults in­di­cate Cs flux fluc­tu­ates at con­stant set­tings, which must be ac­counted for to in­ter­pret graphite get­ter­ing re­sults. Fu­ture stud­ies to iden­tify the cause of fluc­tu­a­tions are con­sid­ered, and a more rig­or­ous ex­per­i­ment to study the use of graphite is in­tro­duced.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL057  
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TUPAL067 Accelerators Validating Antimatter Physics proton, antiproton, electron, FEL 1167
 
  • C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 721559.
The Extra Low En­ergy An­tipro­ton ring (ELENA) will be a crit­i­cal up­grade to the unique An­tipro­ton De­cel­er­a­tor fa­cil­ity at CERN and is cur­rently being com­mis­sioned. ELENA will sig­nif­i­cantly en­hance the achiev­able beam qual­ity and en­able new ex­per­i­ments. To fully ex­ploit the dis­cov­ery po­ten­tial of this fa­cil­ity, ad­vances are ur­gently re­quired in nu­mer­i­cal tools that can ad­e­quately model beam trans­port, life time and in­ter­ac­tion, beam di­ag­nos­tics tools and de­tec­tors to fully char­ac­ter­ize the beam's prop­er­ties, as well as in novel ex­per­i­ments that ex­ploit the en­hanced beam qual­ity that ELENA will pro­vide. These three areas form the sci­en­tific work pack­ages of the new pan-Eu­ro­pean re­search and train­ing ini­tia­tive AVA (Ac­cel­er­a­tors Val­i­dat­ing An­ti­mat­ter physics). The pro­ject has re­ceived around 4M€ of fund­ing and brings to­gether uni­ver­si­ties, re­search cen­ters and in­dus­try to train 15 Fel­lows through re­search in this area. This con­tri­bu­tion pre­sents the re­search re­sults across AVA's three sci­en­tific work pack­ages. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL067  
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TUPAL069 Experimental Demonstration of Ion Beam Cooling with Pulsed Electron Beam electron, synchrotron, simulation, data-analysis 1174
 
  • Y. Zhang, A. Hutton, K. Jordan, T. Powers, R.A. Rimmer, M. F. Spata, H. Wang, S. Wang, H. Zhang
    JLab, Newport News, Virginia, USA
  • J. Li, X.M. Ma, L.J. Mao, M.T. Tang, J.C. Yang, X.D. Yang, H. Zhao, H.W. Zhao
    IMP/CAS, Lanzhou, People's Republic of China
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Cool­ing ion beams at high en­ergy is presently con­sid­ered for sev­eral ion col­lid­ers, in order to achieve high lu­mi­nosi­ties by en­abling a sig­nif­i­cant re­duc­tion of emit­tance of hadron beams. Elec­tron beam at cool­ing chan­nel in a few to tens MeV can be ac­cel­er­ated by a RF/SRF linac, and thus using bunched elec­trons to cool bunched ions. To study such cool­ing process, the DC elec­tron gun of EC35 cooler at the stor­age ring CSRm, IMP was mod­i­fied by puls­ing the grid volt­age. A 0.07-3.5 mi­cro-sec­ond pulse length with a rep­e­ti­tion fre­quency of less than 250 kHz and syn­chro­nized with the ion rev­o­lu­tion fre­quency was ob­tained. The first ex­per­i­men­tal demon­stra­tion of cool­ing of a coast­ing and bunched ion beam by a pulsed elec­tron beam was car­ried out. Data analy­sis in­di­cates the bunch length shrink­age and the mo­men­tum spread re­duc­tion of bunched 12C+6 ion beam as ev­i­dence of cool­ing. A lon­gi­tu­di­nal group­ing ef­fect of the coast­ing ion beam by the elec­tron pulses has also been ob­served*. In this paper, we will pre­sent ex­per­i­men­tal re­sults and com­par­i­son to the sim­u­la­tion mod­el­ling, par­tic­u­larly on the bunched elec­tron cool­ing data after care­fully an­a­lyz­ing the beam di­ag­nos­tic sig­nals.
* L.J. Mao et al., Experimental Demonstration of Electron Cooling with Bunched Electron Beam, TUP15, Proceedings of COOL2017, Bonn, Germany 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL069  
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TUPAL076 Result of the First Muon Acceleration with Radio Frequency Quadrupole rfq, acceleration, simulation, target 1190
 
  • R. Kitamura
    University of Tokyo, Tokyo, Japan
  • S. Bae, B. Kim
    SNU, Seoul, Republic of Korea
  • Y. Fukao, K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, M. Otani, T. Yamazaki
    KEK, Tsukuba, Japan
  • K. Hasegawa, Y. Kondo, T. Morishita
    JAEA/J-PARC, Tokai-mura, Japan
  • H. Iinuma, Y. Nakazawa
    Ibaraki University, Ibaraki, Japan
  • G.P. Razuvaev
    Budker INP & NSU, Novosibirsk, Russia
  • N. Saito
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • Y. Sue
    Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
  
  Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP16H03987, and JP16J07784.
J-PARC E34 ex­per­i­ment aims to mea­sure the muon g-2/EDM pre­cisely with novel tech­niques in­clud­ing the muon lin­ear ac­cel­er­a­tor. Slow muon source by the metal foil method in order to cool the muon beam has been de­vel­oped for the muon ac­cel­er­a­tion test with RF ac­cel­er­a­tor, be­cause the muon beam de­rived from the pro­ton dri­ver was the ter­tiary beam and has a large emit­tance. The first ver­i­fi­ca­tion test of the muon ac­cel­er­a­tion with RFQ was car­ried out at the muon test beam line of J-PARC MLF in Oc­to­ber 2017. The in­ci­dent sur­face muons were de­cel­er­ated by the thin metal foil tar­get and pro­duced the neg­a­tive muo­nium ions (Mu-), which is the bound stat of a pos­i­tive muon and two elec­trons. After Mu- were ex­tracted by a elec­tro­sta­tic ac­cel­er­a­tor as the in­jec­tor of the RFQ, they were ac­cel­er­ated with RFQ to 88.6 keV. The ac­cel­er­ated Mu- were iden­ti­fied by the mo­men­tum se­lec­tion with the bend­ing mag­net after the RFQ, and the mea­sure­ment of the Time-Of-Flight. Ac­cel­er­ated Mu- were eas­ily dis­tin­guished from pen­e­trated pos­i­tive muons by the dif­fer­ence of the po­lar­ity. The lat­est analy­sis re­sult of the world's first muon ac­cel­er­a­tion with RFQ will be re­ported in this paper. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL076  
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TUPAL077 2D-3D PIC Code Benchmarking/Anchoring Comparisons For a Novel RFQ/RFI LINAC Design rfq, space-charge, simulation, linac 1194
 
  • S.J. Smith, S. Biedron, A. M. N. Elfrgani, E. Schamiloglu
    University of New Mexico, Albuquerque, USA
  • M.S. Curtin, B. Hartman, T. Pressnall, D.A. Swenson
    Ion Linac Systems, Inc., Albuquerque, USA
  • K. Kaneta
    CICS, Tokyo, Japan
  
  Funding: *The study at the University of New Mexico was supported in part by DARPA Grant N66001-16-1-4042 and gift to the University of New Mexico Foundation by ILS.
In this study, com­par­isons are made be­tween sev­eral par­ti­cle dy­nam­ics codes (namely CST Par­ti­cle Stu­dio, GPT, and up­graded PARMILA codes) in order to bench­mark them. The struc­ture used for the sim­u­la­tions is a novel 200 MHz, 2.5 MeV, CW RFQ/RFI LINAC de­signed by Ion Linac Sys­tems (ILS). The struc­ture de­sign and pa­ra­me­ters are pro­vided, sim­u­la­tion tech­niques are ex­plained, and re­sults from all three code fam­i­lies are pre­sented. These re­sults are then com­pared with each other, iden­ti­fy­ing sim­i­lar­i­ties and dif­fer­ences. Nu­mer­ous pa­ra­me­ters for com­par­i­son are used, in­clud­ing the trans­mis­sion ef­fi­ciency, Q-fac­tor, E-field on axis, and beam prop­er­ties. Pre­lim­i­nary an­chor­ing be­tween mod­el­ing and sim­u­la­tion per­for­mance pre­dic­tions and ex­per­i­men­tal mea­sure­ments will be pro­vided. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL077  
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TUZGBE4 Toward High-Power High-Gradient Testing of mm-Wave Standing-Wave Accelerating Structures coupling, cavity, accelerating-gradient, diagnostics 1224
 
  • E.A. Nanni, V.A. Dolgashev, A.A. Haase, J. Neilson, S.G. Tantawi
    SLAC, Menlo Park, California, USA
  • S. Jawla, R.J. Temkin
    MIT/PSFC, Cambridge, Massachusetts, USA
  • S. C. Schaub
    MIT, Cambridge, Massachusetts, USA
  • B. Spataro
    INFN/LNF, Frascati (Roma), Italy
  
  Funding: This work is supported in part by Department of Energy contract DE-AC02-76SF00515 (SLAC) and DE-SC0015566 (MIT).
We will pre­lim­i­nary test­ing re­sults for sin­gle-cell ac­cel­er­at­ing struc­tures in­tended for high-gra­di­ent test­ing at 110 GHz. The pur­pose of this work is to study the basic physics of ul­tra­high vac­uum RF break­down in high-gra­di­ent RF ac­cel­er­a­tors. The ac­cel­er­at­ing struc­tures con­sist of pi-mode stand­ing-wave cav­i­ties fed with TM01 cir­cu­lar wave­guide mode. We fab­ri­cated of two struc­tures one in cop­per and the other in CuAg alloy. Cold RF tests con­firm the de­sign RF per­for­mance of the struc­tures. The geom­e­try and field shape of these ac­cel­er­at­ing struc­tures is as close as prac­ti­cal to sin­gle-cell stand­ing-wave X-band ac­cel­er­at­ing struc­tures more than 40 of which were tested at SLAC. This wealth of X-band data will serve as a base­line for these 110 GHz tests. The struc­tures will be pow­ered with a MW gy­ro­tron os­cil­la­tor that pro­duces mi­crosec­ond pulses. One megawatt of RF power from the gy­ro­tron may allow us to reach a peak ac­cel­er­at­ing gra­di­ent of 400 MeV/m. 		 
slides icon Slides TUZGBE4 [4.644 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUZGBE4  
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TUZGBE5 A Combined Temperature and Magnetic Field Mapping System for SRF Cavities cavity, operation, SRF, niobium 1228
 
  • J.M. Köszegi, K. Alomari, J. Knobloch, O. Kugeler, B. Schmitz
    HZB, Berlin, Germany
  
  In the past decade, a sig­nif­i­cant im­prove­ment of SRF cav­ity per­for­mance has been achieved, yet a num­ber of per­for­mance lim­it­ing mech­a­nisms, such as mag­netic flux trap­ping, still exist. We pre­sent a di­ag­nos­tics tool which com­bines flux ex­pul­sion mea­sure­ment dur­ing the su­per­con­duct­ing phase tran­si­tion with tem­per­a­ture map­ping dur­ing op­er­a­tion. This sys­tem has a time res­o­lu­tion for both tem­per­a­ture and mag­netic field map­ping of 2 ms for full cav­ity cov­er­age, so that short-lived events, in­clud­ing cav­ity quenches, can eas­ily be re­solved.  
slides icon Slides TUZGBE5 [1.358 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUZGBE5  
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TUPMF008 Design, Construction, and Magnetic Field Measurements of a Helical Superconducting Undulator for the Advanced Photon Source undulator, photon, storage-ring, electron 1263
 
  • M. Kasa, S.J. Bettenhausen, J.D. Fuerst, E. Gluskin, Q.B. Hasse, Y. Ivanyushenkov, I. Kesgin, Y. Shiroyanagi, E. Trakhtenberg
    ANL, Argonne, Illinois, USA
  
  Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
A he­li­cal su­per­con­duct­ing un­du­la­tor (HSCU) was de­vel­oped and in­stalled at the Ad­vanced Pho­ton Source (APS). Im­ple­men­ta­tion of a unique de­sign of the he­li­cal coil for­mer al­lowed for a com­pact turn around scheme of the con­duc­tor at the ends of the de­vice dur­ing wind­ing. In­her­ent to the coil wind­ing de­sign was the grad­ual re­duc­tion of the mag­ni­tude of the mag­netic field at the ends of the de­vice. The coil for­mer de­sign along with the mag­netic mea­sure­ment re­sults will be de­scribed. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF008  
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TUPMF016 Application of SVD Analysis to Deflecting Cavitiy Space Harmonics cavity, simulation, timing, data-analysis 1283
 
  • C. Yao, L. Emery, D. Hui, H. Shang, Y.P. Sun
    ANL, Argonne, Illinois, USA
  
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Sin­gu­lar value de­com­po­si­tion (SVD) analy­sis is a pow­er­ful tool for iden­ti­fy­ing dif­fer­ent spa­tial and tim­ing vari­a­tion pat­terns in many fields of re­searches. Re­cently we ap­plied com­plex SVD method to space har­monic analy­sis of a 13-cell de­fect­ing cav­ity that is built and in­stalled in the APS linac in­jec­tor for beam phase space char­ac­ter­i­za­tion and emit­tance ex­change ex­per­i­ments. Real and imag­i­nary space har­mon­ics com­po­nents are ex­tracted from CST sim­u­lated data. Fields in­side the iris were ex­pressed in an­a­lytic forms and pro­duced good agree­ment. Work is un­der­way to im­ple­ment the re­sults into el­e­gant sim­u­la­tion model. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF016  
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TUPMF034 Measuring the Electrical Center and Field Flatness of 704 MHz Deflecting Cavity for LEReC with Wire Stretching System cavity, simulation, diagnostics, pick-up 1320
 
  • T. Xin, J.M. Brennan, J.C.B. Brutus, K. Mernick, K.S. Smith, B. P. Xiao, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
  • W. Johnson
    SBU, Stony Brook, New York, USA
  • H. Wang
    JLab, Newport News, Virginia, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
704 MHz de­flect­ing cav­ity was de­signed for the Low En­ergy RHIC elec­tron Cool­ing (LEReC) pro­ject. The cav­ity will serve as a major com­po­nent in di­ag­nos­tic line. In LEReC pro­ject the re­quire­ment on the en­ergy spread of the elec­tron beam is ex­tremely high (bet­ter than 10-4) and the di­ag­nos­tic sys­tem has to to be de­signed ac­cord­ingly. The 704 MHz trans­verse de­flect­ing cav­ity pro­vides the ver­ti­cal kick to the beam after it passes through the dis­per­sion di­pole so that we can mea­sure the en­ergy spread of the core of the bunch. Tra­di­tional way of de­ter­min­ing the elec­tri­cal cen­ter of the cav­ity in­volves the nee­dle pulling and in­te­gra­tion of the sig­nal which is prone to the cu­mu­la­tive error. We pre­sent the mea­sure­ment re­sult from a wire stretch­ing sys­tem that is much more ef­fi­cient and ac­cu­rate com­pared to the bead/nee­dle pulling method. Both sim­u­la­tion and ex­per­i­men­tal re­sults are shown in this paper and the po­ten­tial in fur­ther ap­pli­ca­tion is dis­cussed at the end. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF034  
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TUPMF035 First Demonstration of the Transparent Fast-to-slow Corrector Current Shift in the NSLS-II Storage Ring feedback, lattice, operation, photon 1323
 
  • X. Yang, V.V. Smaluk, Y. Tian, L. Yu
    BNL, Upton, Long Island, New York, USA
  
  To re­al­ize the full ben­e­fits of the high bright­ness and ul­tra-small beam sizes of NSLS-II, it is es­sen­tial that the pho­ton beams are ex­ceed­ingly sta­ble (a level of 10% beam size). In the cir­cum­stances of im­ple­ment­ing local bumps, chang­ing ID gaps, and long-term drift­ing, the fast orbit feed­back (FOFB) re­quires shift­ing the fast cor­rec­tor strengths to the slow cor­rec­tors to pre­vent the fast cor­rec­tor sat­u­ra­tion and to make the beam orbit sta­ble in the sub-mi­cron level. As the re­sult, a re­li­able and pre­cise tech­nique of fast-to-slow cor­rec­tor strength shift has been de­vel­oped and tested at NSLS-II. This tech­nique is based on the fast cor­rec­tor re­sponse to the slow cor­rec­tor change when the FOFB is on. In this ar­ti­cle, the shift tech­nique is de­scribed and the re­sult of proof-of-prin­ci­ple ex­per­i­ment car­ried out at NSLS-II is pre­sented. The max­i­mum fast cor­rec­tor cur­rent was re­duced from greater than 0.45 A to less than 0.04 A with the orbit per­tur­ba­tion within ±1 μm. Es­pe­cially when the step size of the shift was below 0.012 A, the amount of noise being added to the beam was none.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF035  
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TUPMF065 The Role of Electron-Phonon Scattering in Transverse Momentum Conservation in PbTe(111) Photocathodes electron, scattering, photon, cathode 1414
 
  • J. K. Nangoi, T.A. Arias
    Cornell University, Ithaca, New York, USA
  • S.S. Karkare, H.A. Padmore
    LBNL, Berkeley, California, USA
  • W.A. Schroeder
    UIC, Chicago, Illinois, USA
  
  Funding: The U.S. National Science Foundation under Award PHY-1549132, the Center for Bright Beams.
The state of the art in cre­at­ing high qual­ity elec­tron beams for par­ti­cle ac­cel­er­a­tor ap­pli­ca­tions and next gen­er­a­tion ul­tra­fast elec­tron dif­frac­tion and mi­croscopy in­volves laser-gen­er­ated pho­toe­mis­sion. A high qual­ity beam re­quires that elec­trons emerge from the sur­face with low mean trans­verse en­ergy (MTE). Re­cent den­sity-func­tional the­ory cal­cu­la­tions by T. Li and W. A. S. [arXiv:1704.00194v1 [physics.​acc-ph] (2017)] sug­gest that PbTe(111) will pro­duce low-MTE pho­to­elec­trons due to the low ef­fec­tive elec­tron mass as­so­ci­ated with its elec­tronic band struc­ture. Based on this, we mea­sured the dis­tri­b­u­tion of pho­to­elec­trons from PbTe(111) and found the MTE to be about 20x larger than ex­pected. To ex­plain the ap­par­ent lack of trans­verse mo­men­tum con­ser­va­tion, we car­ried out many-body pho­toe­mis­sion cal­cu­la­tions in­clud­ing elec­tron-phonon scat­ter­ing. Our re­sults are in far bet­ter agree­ment with the ex­per­i­ment, un­der­scor­ing the im­por­tance of elec­tron-phonon scat­ter­ing in pho­toe­mis­sion from PbTe(111), and sug­gest that cool­ing could mit­i­gate the phonon ef­fects on the MTE for this ma­te­r­ial. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF065  
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TUPMF072 Microwave Instability and Energy Spread Measurement via Vertical Dispersion Bump in PETRA III emittance, undulator, quadrupole, wiggler 1427
 
  • Y.-C. Chae, D. Dzhingaev, M. Ebert, G. Falkenberg, J. Keil, G. Kube, G.K. Sahoo, M. Sprung, R. Wanzenberg, F. Westermeier
    DESY, Hamburg, Germany
  • A.I. Novokshonov
    TPU, Tomsk, Russia
  
  The re­cent mea­sure­ment of bunch length ver­sus cur­rent in­di­cated that the lon­gi­tu­di­nal im­ped­ance (Z/n) is 0.15 Ω in close agree­ment with the im­ped­ance model*. Naive ap­pli­ca­tion of Keil-Schnell cri­te­ria pre­dicts the thresh­old of mi­crowave in­sta­bil­ity at 0.25 mA. Since the sin­gle bunch in­ten­sity is in the range of 0.2-2.5 mA de­pend­ing on the fill-pat­tern of PETRA III, we ex­pect to ob­serve the fill-pat­tern de­pen­dent en­ergy spread ac­cord­ing to the the­ory. How­ever, the 3rd gen­er­a­tion light sources com­pa­ra­ble to PETRA III often re­ported the ob­ser­va­tion which was much greater than the the­o­ret­i­cal one. In order to in­duce the beam size vari­a­tion we had used skew quadrupoles to gen­er­ate the dis­per­sion in ver­ti­cal plane. In par­tic­u­lar we made dis­per­sion bump at the un­du­la­tor sec­tor so that we were able to use the X-ray op­tics for the pre­cise de­ter­mi­na­tion of small ver­ti­cal beam size. In this paper we re­port the ex­per­i­men­tal setup and mea­sure­ment data with the es­ti­mate on the in­sta­bil­ity thresh­old. We also re­port the ver­ti­cal emit­tance and en­ergy spread based on the X-ray beam size mea­sure­ment as well as the RF sig­nal which was ex­cited by the beam at the lon­gi­tu­di­nal feed­back cav­ity.
* K. Balewski, R. Wanzenberg, "OBSERVATION OF INTENSITY DEPENDENT SINGLE BUNCH EFFECTS AT THE SYNCHROTRON LIGHT SOURCE PETRA III", Proc. of IPAC2011, p. 730. 		 
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TUPMF078 Control of FEL Radiation Properties by Tailoring the Seed Pulses FEL, laser, electron, simulation 1444
 
  • V. Grattoni, R.W. Aßmann, J. Bödewadt, I. Hartl, C. Lechner, B. Manschwetus, M.M. Mohammad Kazemi
    DESY, Hamburg, Germany
  • A. Azima, W. Hillert, V. Miltchev, J. Roßbach
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  • S. Khan, T. Plath
    DELTA, Dortmund, Germany
  
  Seeded free-elec­tron lasers (FELs) pro­duce in­tense, ul­tra­short and fully co­her­ent X-ray pulses. These seeded FEL pulses de­pend on the ini­tial seed prop­er­ties. There­fore, con­trol­ling the seed laser al­lows tai­lor­ing the FEL ra­di­a­tion for phase-sen­si­tive ex­per­i­ments. In this con­tri­bu­tion, we pre­sent de­tailed sim­u­la­tion stud­ies to char­ac­ter­ize the FEL process and to pre­dict the op­er­a­tion per­for­mance of seeded pulses. In ad­di­tion, we show ex­per­i­men­tal data on the tem­po­ral char­ac­ter­i­za­tion of the seeded FEL pulses per­formed at the sFLASH ex­per­i­ment in Ham­burg.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF078  
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TUPMF085 Status of the sFLASH Experiment FEL, electron, laser, photon 1471
 
  • C. Lechner, R.W. Aßmann, J. Bödewadt, V. Grattoni, I. Hartl, T. Laarmann, M.M. Mohammad Kazemi, A. Przystawik
    DESY, Hamburg, Germany
  • A. Azima, H.B. Biss, M. Drescher, W. Hillert, L.L. Lazzarino, V. Miltchev, J. Roßbach
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  • S. Khan, T. Plath
    DELTA, Dortmund, Germany
  
  Funding: This work is supported by the Federal Ministry of Education and Research of Germany within FSP-302 under FKZ 05K13GU4, 05K13PE3, and 05K16PEA.
The sFLASH ex­per­i­ment at the free-elec­tron laser (FEL) FLASH1 is a setup for the in­ves­ti­ga­tion of ex­ter­nal FEL seed­ing. Since 2015, the seed­ing scheme high-gain har­monic gen­er­a­tion (HGHG) is being stud­ied. At the end of the seeded FEL, an RF de­flec­tor en­ables time-re­solved analy­sis of the seeded elec­tron bunches while the pho­ton pulses can be char­ac­ter­ized using the tech­nique of THz streak­ing. In this con­tri­bu­tion, we pre­sent the cur­rent con­fig­u­ra­tion of the ex­per­i­ment and give an overview of re­cent ex­per­i­men­tal re­sults. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF085  
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TUPMK005 CSR Shielding Effect in Dogleg and EEX Beamlines shielding, dipole, simulation, emittance 1498
 
  • G. Ha, M.E. Conde, J.G. Power, E.E. Wisniewski
    ANL, Argonne, Illinois, USA
  
  Funding: Department of Energy, Office of HEP and BES under Contract No. DE-AC02-06CH11357.
CSR shield­ing is a well-known CSR sup­pres­sion scheme which works by cut­ting off the low fre­quency CSR ra­di­a­tion. Al­though the shield­ing scheme is well known, its ef­fects on the beam has been rarely stud­ied. We in­ves­ti­gate the CSR ef­fect on the beam emit­tance when pass­ing through a dog­leg and a dou­ble dog­leg type EEX beam­line. An ex­per­i­men­tal study is planned at the Ar­gonne Wake­field Ac­cel­er­a­tor fa­cil­ity where we can gen­er­ate a 0.1-100 nC elec­tron beam with an en­ergy of 50 MeV and have a dou­ble dog­leg EEX beam­line. Tun­able shield­ing plates are in­stalled at the di­pole mag­net cham­bers of the EEX beam­line to vary the shield­ing con­di­tion. Trans­verse and lon­gi­tu­di­nal phase space mea­sure­ment sys­tems are pre­pared to char­ac­ter­ize the beam-CSR in­ter­ac­tion, and bolome­ter and in­ter­fer­om­e­try are pre­pared to char­ac­ter­ize CSR. We pre­sent sim­u­la­tion re­sults and pre­lim­i­nary ex­per­i­men­tal re­sults. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMK005  
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TUPMK015 Initial Studies into Longitudinal Ionization Cooling for the Muon g-2 Experiment emittance, simulation, storage-ring, target 1522
 
  • J. Bradley
    Edinburgh University, Edinburgh, United Kingdom
  • J.D. Crnkovic
    BNL, Upton, Long Island, New York, USA
  • D. Stratakis, M.J. Syphers
    Fermilab, Batavia, Illinois, USA
  • M.J. Syphers
    Northern Illinois University, DeKalb, Illinois, USA
  
  Fer­mi­lab's Muon g-2 ex­per­i­ment aims to mea­sure the anom­alous mag­netic mo­ment of the muon to an un­prece­dented pre­ci­sion of 140 ppb. It re­lies on large num­bers of muons sur­viv­ing many turns in the stor­age ring with­out col­lid­ing with the sides, at least long enough for the muons to decay. Lon­gi­tu­di­nal ion­iza­tion cool­ing is in­tro­duced with re­spect to Fer­mi­lab's Muon g-2 ex­per­i­ment in an at­tempt to in­crease stor­age and through this the sta­tis­tics and qual­ity of re­sults. The ion­iza­tion cool­ing is in­tro­duced to the beam through a ma­te­r­ial wedge, an ini­tial sim­u­la­tion study is made into the po­si­tion­ing, ma­te­r­ial, and geo­met­ri­cal pa­ra­me­ters of this wedge using G4Beam­line. Re­sults sug­gest a sig­nif­i­cant in­crease of 20 - 30% in the num­ber of stored muons when the op­ti­mal wedge is in­cluded in the sim­u­la­tion.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMK015  
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TUPMK016 Using Time Evolution of the Bunch Structure to Extract the Muon Momentum Distribution in the Fermilab Muon g-2 Experiment positron, storage-ring, bunching, injection 1526
 
  • W. Wu, B. Quinn
    UMiss, University, Mississippi, USA
  • J.D. Crnkovic
    BNL, Upton, Long Island, New York, USA
  
  Beam dy­nam­ics plays an im­por­tant role in achiev­ing the un­prece­dented pre­ci­sion on mea­sure­ment of the muon anom­alous mag­netic mo­ment in the Fer­mi­lab Muon g-2 Ex­per­i­ment. It needs to find the muon mo­men­tum dis­tri­b­u­tion in the stor­age ring in order to eval­u­ate the elec­tric field cor­rec­tion to muon anom­alous pre­ces­sion fre­quency. We will show how to use time evo­lu­tion of the beam bunch struc­ture to ex­tract the muon mo­men­tum dis­tri­b­u­tion by ap­ply­ing a fast ro­ta­tion analy­sis on the decay elec­tron sig­nals.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMK016  
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TUPMK018 Round Beam Studies at NSLS-II coupling, emittance, resonance, lattice 1529
 
  • Y. Hidaka, W.X. Cheng, Y. Li, T.V. Shaftan, G.M. Wang
    BNL, Upton, Long Island, New York, USA
  
  Funding: The study is supported by U.S. DOE under Contract No. DE-AC02-98CH10886.
In­stead of typ­i­cal flat beam, some syn­chro­tron light us-ers pre­fer round beam, i.e., with equal hor­i­zon­tal and ver­ti­cal emit­tance, for var­i­ous rea­sons (e.g., sim­pli­fied op­tics, smaller frac­tion of pho­tons get­ting dis­carded, bet­ter phase space match be­tween pho­ton and e-beam). Sev­eral fu­ture up­grade stor­age rings such as APS-U, ALS-U, and SLS-2 cur­rently plan to op­er­ate in round beam mode. We re­port our beam study re­sults on round beam op­er­at­ing at NSLS-II by dri­ving lin­ear dif­fer­ence cou-pling res­o­nance. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMK018  
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TUPML006 Updates of the Argonne Cathode Test-stand cathode, laser, electron, gun 1542
 
  • J.H. Shao, M.E. Conde, D.S. Doran, W. Gai, W. Liu, J.F. Power, C. Whiteford, E.E. Wisniewski, L.M. Zheng
    ANL, Argonne, Illinois, USA
  • S.P. Antipov, G. Chen, E. Gomez, C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • S.V. Baryshev
    Michigan State University, East Lansing, Michigan, USA
  
  The Ar­gonne Cath­ode Test-stand (ACT) is a unique test­bed to de­velop cath­odes and to con­duct fun­da­men­tal sur­face study under ul­tra-high rf field (up to 700 MV/m with pin-shaped cath­odes). The test-stand con­sists of an L-band 1.3 GHz sin­gle-cell pho­to­cath­ode rf gun and a field emis­sion (FE) imag­ing sys­tem to lo­cate emit­ters with a res­o­lu­tion of ∼20 𝜇m. In the re­cent up­grade, UV laser has been in­tro­duced to im­prove the imag­ing sys­tem and to sig­nif­i­cantly ex­pand the ACT to­wards pho­toe­mis­sion and laser-as­sisted field emis­sion re­search. In ad­di­tion, a load-lock sys­tem has been added to the beam line to ex­pe­dite the cath­ode switch­ing pe­riod. The paper will pre­sent de­tails of the up­grade as well as ex­per­i­ments planned in the near fu­ture.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML006  
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TUPML007 Short Pulse High Power RF Generation with an X-Band Dielectric Power Extractor simulation, acceleration, linear-collider, collider 1546
 
  • J.H. Shao, M.E. Conde, D.S. Doran, W. Gai, W. Liu, N.R. Neveu, J.F. Power, C. Whiteford, E.E. Wisniewski, L.M. Zheng
    ANL, Argonne, Illinois, USA
  • C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio, USA
  
  Short pulse high power rf gen­er­a­tion is one of the key tech­nolo­gies for the Ar­gonne Flex­i­ble Lin­ear Col­lider (AFLC), a pro­posed 3 TeV elec­tron-positron lin­ear col­lider based on two-beam ac­cel­er­a­tion (TBA) scheme. Com­pared with metal­lic power ex­trac­tors, di­elec­tric struc­tures have the po­ten­tial to achieve lower fab­ri­ca­tion cost and to with­stand higher gra­di­ent. Re­cently, an X-band di­elec­tric power ex­trac­tor (a.k.a, DPETS) has been de­vel­oped at the Ar­gonne Wake­field Ac­cel­er­a­tor (AWA) fa­cil­ity and achieved 105 MW out­put power when dri­ven by a high charge 8-bunch train sep­a­rated by 770 ps. The de­sign, the cold test mea­sure­ment, the pre­lim­i­nary high power test re­sults, and the struc­ture in­spec­tion will be pre­sented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML007  
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TUPML009 Design and Test Plan for a Prototype Corrugated Waveguide GUI, wakefield, simulation, electron 1550
 
  • G.J. Waldschmidt, D.S. Doran, G. Ha, R. Kustom, A. Nassiri, J.G. Power, A. Zholents
    ANL, Argonne, Illinois, USA
  • A.E. Siy
    UW-Madison/PD, Madison, Wisconsin, USA
  
  A cylin­dri­cal, cor­ru­gated wake­field ac­cel­er­at­ing struc­ture with a 1 mm ra­dius bore is being de­signed to fa­cil­i­tate sub-ter­a­hertz Čerenkov ra­di­a­tion pro­duced by an elec-tron bunch prop­a­gat­ing along the wave­guide. A 220 GHz axial mode for the wake­field is being con­sid­ered. The wave­guide is being op­ti­mized to max­i­mize the trail­ing wake­field po­ten­tial while main­tain­ing a ratio of the trail-ing po­ten­tial to the peak de­cel­er­at­ing volt­age in the bunch, or trans­former ratio, of ap­prox­i­mately 5 for the door step peak cur­rent dis­tri­b­u­tion [1]. In order to evalu-ate the man­u­fac­tur­ing tol­er­ances and per­form rf and elec­tron beam test­ing of the wave­guide, a 21 GHz proto-type wave­guide struc­ture will be built con­sist­ing of re-con­fig­urable parts al­low­ing mod­el­ling of var­i­ous fab­rica-tion er­rors. Mea­sure­ments with an elec­tron beam will be per­formed at the Ar­gonne Wake­field Ac­cel­er­a­tor (AWA) test fa­cil­ity. Analy­sis of the ex­per­i­men­tal lay­out has been per­formed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML009  
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TUPML011 Experiments Producing Nanopatterned Electron Beams electron, FEL, bunching, emittance 1553
 
  • L.E. Malin, W.S. Graves, J. Spence, K. Weiss, C. Zhang
    Arizona State University, Tempe, USA
  • R.K. Li, E.A. Nanni, X. Shen, S.P. Weathersby, J. Yang
    SLAC, Menlo Park, California, USA
  
  Funding: Work supported by NSF awards 1632780 and 1231306, DOE award DE-AC02-76SF00515, and the SLAC UED/UEM Initiative Program Development Fund.
RF pho­toin­jec­tors are in­creas­ingly used to image at the nanoscale in much the same way as a Trans­mis­sion Elec­tron Mi­cro­scope (TEM), which are gen­er­ally sub-MeV en­ergy. We have con­ducted elec­tron dif­frac­tion ex­per­i­ments through a thin mem­brane of sin­gle crys­tal sil­i­con using both the TEM and pho­toin­jec­tor, and have been able to model and pre­dict the dif­frac­tion pat­terns using the mul­ti­slice method. A nanopat­terned sin­gle crys­tal sil­i­con grat­ing was also im­aged in the TEM in the bright field, where all but the di­rect beam of the dif­frac­tion pat­tern is blocked, giv­ing high con­trast spa­tial mod­u­la­tions cor­re­spond­ing to the 400 nm pitch grat­ing lith­o­graph­i­cally etched into the sil­i­con. Draw­ing from our pre­vi­ous mul­ti­slice cal­cu­la­tions, we de­ter­mined the crys­tal­lo­graphic ori­en­ta­tion that max­i­mized the con­trast in this spa­tial mod­u­la­tion at the en­ergy of the TEM, giv­ing a bunch­ing fac­tor com­pa­ra­ble to a sat­u­rated FEL. We re­port on these key steps to­ward con­trol of ra­di­a­tion phase and tem­po­ral co­her­ence in an FEL. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML011  
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TUPML014 CO2 CPA Laser Development for User Experiments in Advanced Accelerators and Radiation Sources laser, plasma, optics, operation 1556
 
  • M.N. Polyanskiy, M. Babzien, M.A. Palmer, I. Pogorelsky
    BNL, Upton, Long Island, New York, USA
  
  The ATF* is a Na­tional User Fa­cil­ity for ad­vanced re­search in ac­cel­er­a­tor physics and tech­nol­ogy. The ATF's ter­awatt CO2 laser is a unique sci­en­tific in­stru­ment al­low­ing re­searchers to ex­plorer new par­ti­cle ac­cel­er­a­tion mech­a­nisms and to study light/mat­ter in­ter­ac­tion at an or­der-of-mag­ni­tude longer pho­ton wave­lengths com­pared to the ma­jor­ity of other laser re­search fa­cil­i­ties (λ≈10μm). Con­tin­u­ous de­vel­op­ment over more than two decades brought the ATF's CO2 laser to the limit of peak power achiev­able in a con­ven­tional gas laser MOPA con­fig­u­ra­tion (in ATF's am­pli­fier geom­e­try this is ~0.5 TW in rou­tine op­er­a­tion, and up to 2 TW in some ex­per­i­ments). To over­come this limit, we em­ploy, for the first time in a gas laser, a chirped-pulse am­pli­fi­ca­tion (CPA) scheme. The goal of our cur­rent re­search and de­vel­op­ment ef­fort is to demon­strate 3-5 TW peak power at the sys­tem out­put and to re­li­ably de­liver a large frac­tion of this power as a high-qual­ity beam to a range of user ex­per­i­ments. Achiev­ing this goal will lay the ground work for im­ple­men­ta­tion of a >10 TW mid-IR laser sys­tem "BES­TIA" that is cur­rently being con­structed as a part of the ATF-II pro­ject.
*Accelerator Test Facility at Brookhaven National Laboratory 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML014  
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TUPML015 Influence of Ionization and Beam Quality on Interaction of Tw-Peak Co2 Laser With Hydrogen Plasma laser, plasma, simulation, electron 1560
 
  • P. Kumar, V. Samulyak
    SBU, Stony Brook, USA
  • V. Samulyak, K. Yu
    BNL, Upton, Long Island, New York, USA
  
  3D nu­mer­i­cal sim­u­la­tions of the in­ter­ac­tion of a pow­er­ful CO2 laser with hy­dro­gen jets demon­strat­ing the role of ion­iza­tion and laser beam qual­ity are pre­sented. Sim­u­la­tions are per­formed in sup­port of the plasma wake­field ac­cel­er­a­tor ex­per­i­ments being con­ducted at the BNL Ac­cel­er­a­tor Test Fa­cil­ity (ATF). The CO2 laser at BNL ATF has sev­eral po­ten­tial ad­van­tages for laser wake­field ac­cel­er­a­tion com­pared to widely used solid-state lasers. SPACE, a par­al­lel rel­a­tivis­tic Par­ti­cle-in-Cell code, de­vel­oped at SBU and BNL, has been used in these stud­ies. A nov­elty of the code is its set of ef­fi­cient atomic physics al­go­rithms that com­pute ion­iza­tion and re­com­bi­na­tion rates on the grid and trans­fer them to par­ti­cles. The pri­mary goal of the ini­tial BNL ex­per­i­ments was to char­ac­ter­ize the plasma den­sity by mea­sur­ing the side­bands in the spec­trum of the probe laser. Sim­u­la­tions, that re­solve hy­dro­gen ion­iza­tion and laser spec­tra, help ex­plain sev­eral trends that were ob­served in the ex­per­i­ments.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML015  
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TUPML017 Longitudinal Phase Space Reconstruction at FLASHForward Using a Novel Transverse Deflection Cavity, PolariX-TDS plasma, dipole, simulation, lattice 1567
 
  • R.T.P. D'Arcy, A. Aschikhin, P. González Caminal, V. Libov, J. Osterhoff
    DESY, Hamburg, Germany
  
  The FLASH­For­ward pro­ject at DESY is an in­no­v­a­tive beam-dri­ven plasma-wake­field ac­cel­er­a­tion (PWFA) ex­per­i­ment, aim­ing to ac­cel­er­ate elec­tron beams to GeV en­er­gies over a few cen­time­ters of ion­ized gas. These ac­cel­er­ated beams are as­sessed for their ca­pa­bil­ity to drive a free-elec­tron laser. The ultra short, low emit­tance, and low en­ergy spread prop­er­ties of bunches pro­duced from cer­tain PWFA in­jec­tion schemes nat­u­rally lend them­selves to this task. How­ever, these bunch lengths, typ­i­cally in the few fem­tosec­ond range, are dif­fi­cult to tem­po­rally re­solve with tra­di­tional di­ag­nos­tic meth­ods. In order to lon­gi­tu­di­nally di­ag­nose these bunches it is nec­es­sary to utilise the prop­er­ties of a trans­verse RF de­flect­ing cav­ity op­er­at­ing in a high-fre­quency regime. It is pro­posed that this type of X-band trans­verse de­flec­tion sys­tem, styled the Po­lariX-TDS due to its novel vari­able po­lar­i­sa­tion fea­ture, will be in­tro­duced to the FLASH­For­ward beam line in order to per­form these sin­gle-shot lon­gi­tu­di­nal phase space mea­sure­ments. This paper will con­cern it­self with the ef­fi­cacy of lon­gi­tu­di­nally re­con­struct­ing PWFA-bunches ex­pected at FLASH­For­ward with this TDS, with a focus on the vari­able bunch prop­er­ties ex­pected from early com­mis­sion­ing of the ex­per­i­ment.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML017  
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TUPML020 Beamline Design of EMuS - the First Experimental Muon Source in China solenoid, proton, target, polarization 1574
 
  • Y. Bao, Y.K. Chen, Z.L. Hou, Y.P. Song, J.Y. Tang, N. Vassilopoulos, Y. Yuan, G. Zhao, L. Zhou
    IHEP, Beijing, People's Republic of China
  • H.T. Jing
    IHEP CSNS, Dongguan, People's Republic of China
  
  Funding: This work is supported by National Natural Science Foundation of China under Grants 11575217 and 11527811. Yu Bao thanks Hundred Talents Program of Chinese Academy of Science.
We re­port the beam­line de­sign of the Ex­per­i­men­tal Muon Source (EMuS) pro­ject in China. Based on the 1.6 GeV/100 kW pro­ton ac­cel­er­a­tor at the Chi­nese Spal­la­tion Neu­tron Source (CSNS), EMuS will ex­tract one bunch from every 10 dou­ble-bunch pro­ton pulses to hit a stand-alone tar­get sit­ting in a su­per­con­duct­ing so­le­noid, and the sec­ondary muons/pions are guided to the ex­per­i­men­tal area. The beam­line is de­signed to pro­vide both a sur­face muon beam and a decay muon beam, so that var­i­ous ex­per­i­ments such as muSR ap­pli­ca­tions and par­ti­cle/nu­clear physics ex­per­i­ments can be con­ducted. In this work we pre­sent the con­cep­tual de­sign and sim­u­la­tion of the beam­lines, and dis­cuss the fu­ture as­pects of the pro­ject. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML020  
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TUPML031 Characterization of Polarization-Dependent Emittance From an Array of Au Nanorods using Velocity Map Imaging Spectrometer electron, laser, polarization, emittance 1612
 
  • H. Ye, F.X. Kärtner, S. T. Trippel
    Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany
  • A. Fallahi, J. Küpper, O. Muecke
    CFEL, Hamburg, Germany
  • F.X. Kärtner
    MIT, Cambridge, Massachusetts, USA
  • F.X. Kärtner, J. Küpper, S. T. Trippel, H. Ye
    The Hamburg Center for Ultrafast Imaging, University of Hamburg, hamburg, Germany
  • J. Küpper, G.M. Rossi
    DESY, Hamburg, Germany
  • H. Ye
    University of Hamburg, Hamburg, Germany
  
  Elec­tron beams of high qual­ity, e.g., low emit­tance, are of cru­cial im­por­tance for cut­ting-edge sci­en­tific in­stru­ments, such as x-ray free elec­tron lasers (XFELs) and ul­tra­fast elec­tron dif­frac­tion (UED) se­tups. A ve­loc­ity-map-imag­ing (VMI) spec­trom­e­ter was im­ple­mented to char­ac­ter­ize the in­trin­sic root-mean-square (rms) nor­mal­ized emit­tance from pho­to­cath­odes. The spec­trom­e­ter op­er­ated in both, spa­tial map imag­ing (SMI) and VMI modes. There­fore, spa­tial- and ve­loc­ity-co­or­di­nates were recorded in­de­pen­dently and quickly. The tech­nique al­lows for fast com­plete emit­tance mea­sure­ments, within min­utes. A 75 μm pitch array of Au nanorods of di­men­sion 100×30~nm, was stud­ied under strong-field-emis­sion regime by 100 fs 1 kHz 1.3 μm laser pulses with a 300×30 μm2 focus spot size on the sam­ple. A pat­terned elec­tron bunch was ob­served, each emit­ted from a sin­gle nanorod within the array. A po­lar­iza­tion de­pen­dent pho­toe­mis­sion study was per­formed show­ing a smaller rms-nor­mal­ized di­ver­gence of 0.8 mrad with the laser po­lar­iza­tion nor­mal to the sam­ple sur­face, com­pared to 1.15 mrad for the par­al­lel case.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML031  
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TUPML039 First Order Sensitivity Analysis of Electron Acceleration in Dual Grating Type Dielectric Laser Accelerator Structures laser, electron, simulation, emittance 1626
 
  • F. Mayet, R.W. Aßmann, U. Dorda, W. Kuropka
    DESY, Hamburg, Germany
  • W. Kuropka, F. Mayet
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  
  Funding: Gordon and Betty Moore Foundation. Grant GBMF4744
Sym­met­ri­cally dri­ven dual-grat­ing type DLA (Di­elec­tric Laser Ac­cel­er­a­tor) linac struc­tures allow for in-chan­nel elec­tric field gra­di­ents on the order of GV/m at op­ti­cal wave­lengths. In this work we study the sen­si­tiv­ity of im­por­tant final beam pa­ra­me­ters like mean en­ergy, en­ergy spread and trans­verse emit­tance on DLA drive laser as well as input beam pa­ra­me­ters. To this end a fast spe­cial­ized par­ti­cle track­ing code (DLA­Tracker) is used to com­pute the so called first order sen­si­tiv­ity in­dices based on a large num­ber of Monte Carlo sim­u­la­tion runs of an ex­em­plary ex­ter­nal in­jec­tion based DLA ex­per­i­ment. The re­sults of this work point out im­por­tant sta­bil­ity con­straints on the drive laser setup and the ex­ter­nally in­jected elec­tron beam. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML039  
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TUPML046 Characterization of Self-Modulated Electron Bunches in an Argon Plasma plasma, electron, solenoid, focusing 1645
 
  • M. Groß, P. Boonpornprasert, Y. Chen, J. Engel, J.D. Good, H. Huck, I.I. Isaev, M. Krasilnikov, X. Li, O. Lishilin, G. Loisch, R. Niemczyk, A. Oppelt, H.J. Qian, Y. Renier, F. Stephan, Q.T. Zhao
    DESY Zeuthen, Zeuthen, Germany
  • R. Brinkmann, A. Martinez de la Ossa, J. Osterhoff
    DESY, Hamburg, Germany
  • F.J. Grüner
    CFEL, Hamburg, Germany
  • F.J. Grüner, A. Martinez de la Ossa
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  • T.J. Mehrling, C.B. Schroeder
    LBNL, Berkeley, USA
  • I. Will
    MBI, Berlin, Germany
  
  The self-mod­u­la­tion in­sta­bil­ity is fun­da­men­tal for the plasma wake­field ac­cel­er­a­tion ex­per­i­ment of the AWAKE (Ad­vanced Wake­field Ex­per­i­ment) col­lab­o­ra­tion at CERN where this ef­fect is used to gen­er­ate pro­ton bunches for the res­o­nant ex­ci­ta­tion of high ac­cel­er­a­tion fields. Uti­liz­ing the avail­abil­ity of flex­i­ble elec­tron beam shap­ing to­gether with ex­cel­lent di­ag­nos­tics in­clud­ing an RF de­flec­tor, a sup­port­ing ex­per­i­ment was set up at the elec­tron ac­cel­er­a­tor PITZ (Photo In­jec­tor Test fa­cil­ity at DESY, Zeuthen site), given that the un­der­ly­ing physics is the same. After demon­strat­ing the ef­fect* the next goal is to in­ves­ti­gate in de­tail the self-mod­u­la­tion of long (with re­spect to the plasma wave­length) elec­tron beams. In this con­tri­bu­tion we de­scribe pa­ra­me­ter stud­ies on self-mod­u­la­tion of a long elec­tron bunch in an argon plasma. The plasma was gen­er­ated with a dis­charge cell with den­si­ties in the 1013 cm-3 to 1015 cm-3 range. The plasma den­sity was de­duced from the plasma wave­length as in­di­cated by the self-mod­u­la­tion pe­riod. Pa­ra­me­ter scans were con­ducted with vari­able plasma den­sity and elec­tron bunch fo­cus­ing.
* M. Gross et al., "Observation of the self-modulation instabil-ity via time-resolved measurements", accepted for publication at Phys. Rev. Lett. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML046  
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TUPML049 Comparison of Fourier Signal and Error Analysis Techniques for Identifying the Self-Modulation Frequency of a Proton Bunch plasma, proton, wakefield, electron 1651
 
  • S.J. Gessner
    CERN, Geneva, Switzerland
  
  The AWAKE ex­per­i­ment uses an ul­tra-high en­ergy pro­ton beam to cre­ate large am­pli­tude wake­fields for ac­cel­er­at­ing elec­trons in plasma. The pro­ton beam is much longer than the plasma wave­length, and must be formed into small, sub- wave­length sized beam­lets be­fore it can ef­fec­tively drive the wake. These beam­lets are re­ferred to as mi­cro-bunches and are formed by the plasma self-mod­u­la­tion in­sta­bil­ity. An im- por­tant as­pect of AWAKE is to mea­sure the depth, fre­quency, and sta­bil­ity of the mod­u­la­tion, as this pro­vides crit­i­cal in- for­ma­tion for es­tab­lish­ing the pres­ence of a high-am­pli­tude wake­field dri­ven by a self-mod­u­la­tion pro­ton bunch. This paper dis­cusses Fourier Analy­sis tech­niques for mea­sur­ing the mod­u­la­tion fre­quency and com­pares error es­ti­ma­tion tech­niques that work for both small and large datasets.
On behalf of the AWAKE Collaboration. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML049  
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TUPML051 Studies of Collision and Compression of Pulsed Plasmas Generated by Coaxial Accelerators plasma, electron, ion-source, simulation 1653
 
  • T. Manegold, C. Benzing, M. Iberler, J. Jacoby, P. Mahmoodi Tavana, A. Müller-Münster, B. Podßus
    IAP, Frankfurt am Main, Germany
  
  This con­tri­bu­tion is about our re­cent stud­ies of col­li­sion and com­pres­sion of plasma sheaths, gen­er­ated by coax­ial plasma ac­cel­er­a­tors. One ap­pli­ca­tion is the de­vel­op­ment of a pulsed ion source pro­duc­ing high ion cur­rents, com­ing along with high elec­tron den­si­ties. The ex­per­i­ment is built up of an en­ergy stor­age with up to 1,35kJ with a 2% Hy­dro­gen in He­lium gas mix­ture as work­ing gas. The small frac­tion of Hy­dro­gen is nec­es­sary to use the lin­ear Stark-broad­en­ing of the H-line to de­ter­mine the elec­tron den­sity, which is in the range up to 1015cm-3. By the col­li­sion of two plasma sheaths in an angle of 180°, the elec­tron den­sity has been in­creased by a fac­tor of 2.5 com­pared to the sin­gle plasma sheath. As an al­ter­na­tive, the com­pres­sion of the plasma by fun­nel geome­tries has been stud­ied. As has been found, the achieved elec­tron den­si­ties are more than a mag­ni­tude higher, com­pared to the val­ues of the plasma col­li­sion. Thus, the H-line is broad­ened too high to be used. Al­ter­na­tively, the broad­en­ing of a cop­per line by the qua­dratic Stark-ef­fect has been cal­i­brated and used to de­ter­mine those high elec­tron den­si­ties of about 1018cm-3.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML051  
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TUPML052 Characterisation of the Second Stable Orbit Generated by Transverse Resonance Island Buckets (TRIBs) optics, resonance, emittance, simulation 1656
 
  • F. Kramer, P. Goslawski, A. Jankowiak, M. Ries, M. Ruprecht, A. Schälicke
    HZB, Berlin, Germany
  
  Funding: Federal Ministry of Education and Research
Op­er­at­ing the stor­age ring near a trans­verse tune res­o­nance can gen­er­ate TRIBs in the cor­re­spond­ing phase space, pro­vid­ing a sec­ond orbit twist­ing around the stan­dard orbit. TRIBs as a bunch sep­a­ra­tion scheme in com­bi­na­tion with the pro­posed vari­able bunch length stor­age ring BESSY VSR* rep­re­sent a promis­ing al­ter­na­tive to ded­i­cated sin­gle or few bunch op­er­a­tion modes. The in­jec­tion ef­fi­ciency and sta­bil­ity of the two or­bits at BESSY II and MLS are al­most on par with and the life­time at about 70 % of the stan­dard user mode. Re­sults from sim­u­la­tions and mea­sure­ments of our pre­sent is­land op­tics will be pre­sented. Beam pa­ra­me­ters like the be­ta­tron mo­tion, dis­per­sion and emit­tance of both the core and is­land orbit will be dis­cussed as well as the sep­a­ra­tion be­tween the is­land and the core orbit. At BESSY II a ded­i­cated test week to­gether with the friendly users took place in the first week of Feb­ru­ary, 2018.
* A. Jankowiak et al., eds., BESSY VSR Technical Design Study, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Germany, June 2015. DOI: 10.5442/R0001 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML052  
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TUPML060 Three-Dimentional Spiral Beam Injection for a Compact Storage Ring injection, solenoid, coupling, electron 1673
 
  • H. Iinuma
    Ibaraki University, Hitachi, Ibaraki, Japan
  • M.R. Abdul
    Sokendai, Ibaraki, Japan
  • Y. Fukao, K. Furukawa, H. Hisamatsu, T. Mibe, H. Nakayama, S. Ohsawa, K. Oide, K. Sasaki
    KEK, Tsukuba, Japan
  
  Funding: This work is supported by JSPS KAKENHI Grant Numbers JP26287055 and JP 23740216.
A newly de­vel­oped three-di­men­sional spi­ral in­jec­tion scheme for beam in­ser­tion into a com­pact (med­ical MRI size) so­le­noidal stor­age ring is in­tro­duced. This is a one of key R&D items for a new planned muon g-2/EDM ex­per­i­ment at J-PARC, which aims to mea­sure g-2 to a fac­tor 5 bet­ter sta­tis­ti­cal pre­ci­sion and a fac­tor of 100 bet­ter sen­si­tiv­ity for the elec­tric di­pole mo­ment mea­sure­ment (EDM) com­pared to the pre­vi­ous ex­per­i­ments. The new scheme pro­vides a smooth in­jec­tion uti­liz­ing a ra­dial so­le­noidal fringe field, with­out caus­ing any error field in the stor­age vol­ume. Mag­netic pulsed kicker will guide and set the beam in the stor­age field vol­ume. The strongest point of this new scheme is that any source of the elec­tric field is re­moved in this scheme to per­form ideal EDM mea­sure­ment. We have per­formed a test bench ex­per­i­men­tal work to demon­strate a fea­si­bil­ity of this new in­jec­tion scheme. In­stead of the muon beam, we in­ject elec­tron beam, from an elec­tron-gun, into the so­le­noid mag­net, and de­tect three-di­men­sional spi­ral beam tra­jec­tory in­side of the stor­age cham­ber by CCD cam­era. We will dis­cuss out­line of a new in­jec­tion scheme and the lat­est re­sults from the test bench works.
*H. Iinuma et al.,Nuclear Instruments and Methods in Physics Research A, 832, 51-62 (2016) 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML060  
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TUPML062 A Wedge Test in MICE emittance, beam-cooling, simulation, collider 1680
 
  • T.A. Mohayai
    IIT, Chicago, Illinois, USA
  • D.V. Neuffer
    Fermilab, Batavia, Illinois, USA
  • P. Snopok
    Illinois Institute of Technology, Chicago, Illlinois, USA
  • D.J. Summers
    UMiss, University, Mississippi, USA
  
  Emit­tance ex­change me­di­ated by wedge ab­sorbers is re­quired for lon­gi­tu­di­nal ion­iza­tion cool­ing and for final trans­verse emit­tance min­i­miza­tion for a muon col­lider. A wedge ab­sorber within the MICE cool­ing chan­nel could serve as a demon­stra­tion of the type of emit­tance ex­change needed for 6-D cool­ing, in­clud­ing the con­fig­u­ra­tions needed for muon col­lid­ers. Pa­ra­me­ters for this test have been ex­plored in sim­u­la­tion and ap­plied to ex­per­i­men­tal con­fig­u­ra­tions using a wedge ab­sorber in the MICE beam. A wedge ab­sorber has been con­structed and placed in MICE and data has been col­lected for both di­rect emit­tance ex­change, where the lon­gi­tu­di­nal emit­tance de­creases, and re­verse emit­tance ex­change, where the trans­verse emit­tance de­creases. The sim­u­la­tion stud­ies that led to the mag­net con­fig­u­ra­tions and beam con­fig­u­ra­tions are pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML062  
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TUPML063 A Non-parameteric Density Estimation Approach to Measuring Beam Cooling in MICE emittance, beam-cooling, simulation, solenoid 1684
 
  • T.A. Mohayai
    IIT, Chicago, Illinois, USA
  • D.V. Neuffer
    Fermilab, Batavia, Illinois, USA
  • P. Snopok
    Illinois Institute of Technology, Chicago, Illlinois, USA
  
  The goal of the in­ter­na­tional Muon Ion­iza­tion Cool­ing Ex­per­i­ment (MICE) is to demon­strate muon beam ion­iza­tion cool­ing for the first time. It con­sti­tutes a key part of the R&D to­wards a fu­ture neu­trino fac­tory or muon col­lider. The in­tended MICE pre­ci­sion re­quires de­vel­op­ment of analy­sis tools that can ac­count for any ef­fects (e.g., non­lin­ear­i­ties) which may lead to in­ac­cu­rate cool­ing mea­sure­ments. Non-para­met­ric den­sity es­ti­ma­tion tech­niques, in par­tic­u­lar, ker­nel den­sity es­ti­ma­tion (KDE), allow very pre­cise cal­cu­la­tions of the muon beam phase-space den­sity and its in­crease as a re­sult of cool­ing. In this study, these den­sity es­ti­ma­tion tech­niques and their ap­pli­ca­tion to mea­sur­ing the re­duc­tion in muon beam phase-space vol­ume and am­pli­tude in MICE are in­ves­ti­gated.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML063  
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TUPML064 Staged Two Beam Acceleration Beam Line Design for the AWA Facility kicker, gun, laser, acceleration 1688
 
  • N.R. Neveu
    IIT, Chicago, Illinois, USA
  • W. Gai, C.-J. Jing, J.G. Power
    ANL, Argonne, Illinois, USA
  • C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • L.K. Spentzouris
    Illinois Institute of Technology, Chicago, Illinois, USA
  
  Funding: This work is funded by the DOE Office of Science, grant no. DE-SC0015479, and contract No. DE-AC02- 06CH11357.
Two beam ac­cel­er­a­tion is a can­di­date for fu­ture high en­ergy physics ma­chines and FEL user fa­cil­i­ties. This scheme con­sists of two in­de­pen­dent elec­tron beam lines op­er­at­ing syn­chro­nously. High-charge, 70 MeV drive bunch trains are in­jected from the RF photo-in­jec­tor into de­cel­er­at­ing struc­tures to gen­er­ate a few hun­dred of MW of RF power. This RF power is trans­ferred through an RF wave­guide to ac­cel­er­at­ing struc­tures that are used to ac­cel­er­ate the wit­ness beam. Stag­ing refers to the se­quen­tial ac­cel­er­a­tion (en­ergy gain) in two or more struc­tures on the wit­ness beam line. A kicker was in­cor­po­rated on the drive beam line to ac­com­plish a mod­u­lar de­sign so that each ac­cel­er­at­ing struc­ture can be in­de­pen­dently pow­ered by a sep­a­rate drive beam. Sim­u­la­tions were per­formed in OPAL-T to model the two beam lines. Beam sizes at the cen­ter of the struc­tures was min­i­mized to en­sure good charge trans­mis­sion. The re­sult­ing de­sign will be the basis for proof of prin­ci­ple ex­per­i­ments that will take place at the Ar­gonne Wake­field Ac­cel­er­a­tor (AWA) fa­cil­ity. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML064  
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TUPML065 Phase Space Density Evolution in MICE emittance, simulation, factory, collider 1692
 
  • D. Rajaram
    Illinois Institute of Technology, Chicago, Illinois, USA
  • V. Blackmore
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  
  Funding: STFC, DOE, NSF, INFN, and CHIPP
The Muon Ion­iza­tion Cool­ing Ex­per­i­ment (MICE) col­lab­o­ra­tion will demon­strate the fea­si­bil­ity of ion­iza­tion cool­ing, the tech­nique pro­posed to cool the muon beam at a fu­ture neu­trino fac­tory or muon col­lider. The muon beam pa­ra­me­ters are mea­sured be­fore and after the cool­ing cell using high pre­ci­sion scin­til­lat­ing-fi­bre track­ers in a so­le­noidal mag­netic field. Po­si­tion and mo­men­tum re­con­struc­tion of each muon in MICE al­lows the de­vel­op­ment of sev­eral al­ter­na­tive fig­ures of merit in ad­di­tion to emit­tance. Con­trac­tion of the phase-space vol­ume of the sam­ple, or equiv­a­lently the in­crease in phases-pace den­sity at its core, is an un­equiv­o­cal cool­ing sig­na­ture. Sin­gle-par­ti­cle am­pli­tude, de­fined as a weighted dis­tance to the sam­ple cen­troid, can be used to probe the change in den­sity in the core of the beam. Al­ter­na­tively, non-para­met­ric sta­tis­tics pro­vide re­li­able meth­ods to es­ti­mate the en­tire phase-space den­sity dis­tri­b­u­tion and re­con­struct prob­a­bil­ity con­tours. The afore­men­tioned tech­niques, ro­bust to trans­mis­sion losses and sam­ple non lin­ear­i­ties, are ideal can­di­dates for a cool­ing mea­sure­ment in MICE. Pre­lim­i­nary re­sults are pre­sented here*.
*Submitted by the MICE Speakers bureau, to be prepared and presented by a MICE member to be selected in due course 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML065  
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TUPML067 Recent Results from the Study of Emittance Evolution in MICE emittance, solenoid, detector, lattice 1699
 
  • V. Blackmore
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  
  Funding: STFC, DOE, NSF, INFN, and CHIPP
The Muon Ion­iza­tion Cool­ing Ex­per­i­ment (MICE) has mea­sured the evo­lu­tion of emit­tance due to ion­iza­tion en­ergy loss. Muons were fo­cused onto an ab­sorber using a large aper­ture so­le­noid. Lithium-hy­dride and liq­uid hy­dro­gen-ab­sorbers have been stud­ied. Di­ag­nos­tic de­vices were placed up­stream and down­stream of the focus, en­abling the phase-space co­or­di­nates of in­di­vid­ual muons to be re­con­structed. By ob­serv­ing the prop­er­ties of en­sem­bles of muons, the change in beam emit­tance was mea­sured. Data taken dur­ing 2016 and 2017 are cur­rently under study to eval­u­ate the change in emit­tance due to the ab­sorber for muon beams with var­i­ous ini­tial emit­tance, mo­menta, and set­tings of the mag­netic lat­tice. The cur­rent sta­tus and the most re­cent re­sults of these analy­ses will be pre­sented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML067  
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TUPML071 Experimental Performance of the Chopper for the ESS Linac electron, high-voltage, linac, proton 1709
 
  • G. Torrisi, L. Allegra, A.C. Caruso, G. Castro, L. Celona, G. Gallo, S. Gammino, O. Leonardi, A. Longhitano, D. Mascali, L. Neri, S. Passarello, G. Sorbello
    INFN/LNS, Catania, Italy
  
  At the Is­ti­tuto Nazionale di Fisica Nu­cleare - Lab­o­ra­tori Nazion­ali del Sud (INFN-LNS) the beam com­mis­sion­ing of the high in­ten­sity Pro­ton Source for the Eu­ro­pean Spal­la­tion Source (PS-ESS) was com­pleted in No­vem­ber 2017. The ESS re­quires a high in­ten­sity pro­ton beam (74 mA pulsed at 14 Hz of rep­e­ti­tion rate), with fast Beam pulse rise/fall time (< 20 μs). In order to meet the pro­ject re­quire­ment, an elec­tro­sta­tic chop­ping sys­tem has been used in the Low En­ergy Beam Trans­port (LEBT). The de­sign of the con­trol sys­tem was done also to be the main el­e­ment of the fast beam abort sys­tem and tak­ing into ac­count the ra­di­a­tion issue in the ac­cel­er­a­tor tun­nel. This paper de­scribes the per­for­mances of the chop­per. The ex­per­i­men­tally-achieved rise/fall times of the beam pulses mea­sured by using an AC Cur­rent Trans­former (ACCT) at the end of the LEBT col­li­ma­tor, are pre­sented. An ex­per­i­men­tal in­ves­ti­ga­tion of the ef­fects of dif­fer­ent amounts and types of gas in­jected into the LEBT (for the sake of space charge com­pen­sa­tion) has been car­ried out with re­spect to the beam and chop­per pa­ra­me­ters.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML071  
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TUPML074 Resonant Excitation of Accelerating Field in Dielectric Corrugated Waveguide simulation, wakefield, electron, GUI 1715
 
  • A. Lyapin, S.T. Boogert, K. Lekomtsev
    JAI, Egham, Surrey, United Kingdom
  • A. Aryshev
    KEK, Ibaraki, Japan
  • A.A. Tishchenko
    MEPhI, Moscow, Russia
  
  Funding: This project has received funding from the European Union Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 655179.
Beam dri­ven di­elec­tric wake­field ac­cel­er­a­tors (DWAs) [*] typ­i­cally op­er­ate in the ter­a­hertz fre­quency range, which pushes the plasma break­down thresh­old for sur­face elec­tric fields into the multi GV/m range. DWA tech­nique al­lows one to ac­com­mo­date a sig­nif­i­cant amount of charge per bunch, and opens ac­cess to con­ven­tional fab­ri­ca­tion tech­niques for the ac­cel­er­at­ing struc­tures. Res­o­nant ex­ci­ta­tion of co­her­ent Cherenkov ra­di­a­tion in DWA by a multi-bunch beam was used for se­lec­tive res­o­nant mode ex­ci­ta­tion [**] and en­hance­ment of ac­cel­er­at­ing wake­field [***]. We in­ves­ti­gate the res­o­nant ex­ci­ta­tion of Cherenkov Smith-Pur­cell ra­di­a­tion [****] in a cor­ru­gated cylin­dri­cal wave­guide by a multi-bunch elec­tron beam. The ac­cel­er­at­ing field is cal­cu­lated using Par­ti­cle in Cell sim­u­la­tions and some basic post-pro­cess­ing is done in order to es­ti­mate the pos­si­ble en­hance­ment of the ac­cel­er­at­ing field. The aim of this work is to in­ves­ti­gate regimes of the res­o­nant ex­ci­ta­tion that can po­ten­tially pro­duce ac­cel­er­at­ing gra­di­ents above 1 GV/m.
* C. Jing, Rev. Acc. Phys. and Tech. 9, 127 (2016).
** G. Andonian, APL 98, 202901 (2011).
*** J.G. Power, PRSTAB 3, 101302 (2000).
**** A.A. Ponomarenko, A.A. Tishchenko, NIMB 309, 223 (2013).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML074  
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WEYGBD1 12 GeV CEBAF Initial Operational Experience and Challenges operation, MMI, cryomodule, cavity 1771
 
  • M. F. Spata
    JLab, Newport News, Virginia, USA
  
  The 12 GeV Up­grade for the Con­tin­u­ous Elec­tron Beam Ac­cel­er­a­tor Fa­cil­ity (CEBAF) achieved CD-4B, or Pro­ject Com­ple­tion, on Sep­tem­ber 27, 2017. The 13-year $338M pro­ject dou­bled the beam en­ergy of the CEBAF ac­cel­er­a­tor while also adding a fourth ex­per­i­men­tal hall. The scope of work for the ac­cel­er­a­tor com­plex was com­pleted in 2014. Over the sub­se­quent three years the up­grades for the ex­per­i­men­tal halls were com­pleted, beam­lines and spec­trom­e­ters com­mis­sioned and tran­si­tions made to pro­duc­tion run­ning for the Nu­clear Physics pro­gram. This paper will pre­sent an overview of the op­er­a­tional ex­pe­ri­ence gained dur­ing ini­tial ac­cel­er­a­tor com­mis­sion­ing through the re­cent achieve­ments of si­mul­ta­ne­ous 4-Hall op­er­a­tions at full beam power.  
slides icon Slides WEYGBD1 [15.178 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEYGBD1  
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WEPAF014 Commissioning the Superconducting Magnetic Inflector System for the Muon g-2 Experiment storage-ring, injection, MMI, simulation 1844
 
  • N.S. Froemming
    CENPA, Seattle, Washington, USA
  • K.E. Badgley, H. Nguyen, D. Stratakis
    Fermilab, Batavia, Illinois, USA
  • J.D. Crnkovic
    BNL, Upton, Long Island, New York, USA
  • L.E. Kelton
    UKY, Kentucky, USA
  • M.J. Syphers
    Northern Illinois University, DeKalb, Illinois, USA
  
  The Fer­mi­lab muon g-2 ex­per­i­ment aims to mea­sure the muon anom­alous mag­netic mo­ment with a pre­ci­sion of 140 ppb - a four­fold im­prove­ment over the 540 ppb pre­ci­sion ob­tained in the BNL muon g-2 ex­per­i­ment. Both of these high-pre­ci­sion ex­per­i­ments re­quire an ex­tremely uni­form mag­netic field in the muon stor­age ring. A su­per­con­duct­ing mag­netic in­flec­tor sys­tem is used to in­ject beam into the stor­age ring as close as pos­si­ble to the de­sign orbit while min­i­miz­ing dis­tur­bances to the stor­age-re­gion mag­netic field. The Fer­mi­lab ex­per­i­ment is cur­rently in its first data-tak­ing run, where the Fer­mi­lab in­flec­tor sys­tem is the re­fur­bished BNL in­flec­tor sys­tem. This dis­cus­sion re­views the Fer­mi­lab in­flec­tor sys­tem re­fur­bish­ment and com­mis­sion­ing.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF014  
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WEPAF015 Commissioning the Muon g-2 Experiment Electrostatic Quadrupole System quadrupole, storage-ring, positron, resonance 1848
 
  • J.D. Crnkovic, V. Tishchenko
    BNL, Upton, Long Island, New York, USA
  • K.E. Badgley, H. Nguyen, E. Ramberg
    Fermilab, Batavia, Illinois, USA
  • E. Barlas Yucel, M. Yucel
    Istanbul Technical University, Maslak, Istanbul, Turkey
  • J.M. Grange
    ANL, Argonne, Illinois, USA
  • A.T. Herrod
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A.T. Herrod
    The University of Liverpool, Liverpool, United Kingdom
  • J.L. Holzbauer, W. Wu
    UMiss, University, Mississippi, USA
  • H.D. Sanders
    APP, Freeville, New York, USA
  • H.D. Sanders
    Sanders Pulsed Power LLC, Batavia, Illinois, USA
  • N.H. Tran
    BUphy, Boston, Massachusetts, USA
  
  The Fer­mi­lab Muon g-2 ex­per­i­ment aims to mea­sure the muon anom­aly with a pre­ci­sion of 140 parts-per-bil­lion (ppb) - a four­fold im­prove­ment over the 540 ppb pre­ci­sion ob­tained by the BNL Muon g-2 ex­per­i­ment. These high pre­ci­sion ex­per­i­ments both re­quire a very uni­form muon stor­age ring mag­netic field that pre­cludes the use of ver­ti­cal-fo­cus­ing mag­netic quadrupoles. The Fer­mi­lab Elec­tro­sta­tic Quadru­pole Sys­tem (EQS) is the re­fur­bished and up­graded BNL EQS, where this overview de­scribes the Fer­mi­lab EQS and its re­cent op­er­a­tions.  
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WEPAF016 Application of Quad-Scan Measurement Techniques to Muon Beams in the Muon g-2 Experiment emittance, storage-ring, quadrupole, scattering 1852
 
  • J. Bradley
    Edinburgh University, Edinburgh, United Kingdom
  • J.D. Crnkovic
    BNL, Upton, Long Island, New York, USA
  • B.E. Drendel, D. Stratakis
    Fermilab, Batavia, Illinois, USA
  • N.S. Froemming
    CENPA, Seattle, Washington, USA
  
  De­ter­mi­na­tion of the prop­er­ties of a beam dur­ing trans­port is a vital process for most ac­cel­er­a­tor-re­lated ex­per­i­ments; for ex­am­ple Fer­mi­lab's Muon g-2 ex­per­i­ment re­quires large num­bers of muons to be stored in a stor­age ring of 7 meter ra­dius, and the trans­mis­sion frac­tion has been shown to de­pend strongly on the prop­er­ties of the beam, specif­i­cally the Twiss pa­ra­me­ters. The cur­rent equip­ment in the muon cam­pus beam­lines al­lows only mea­sure­ment of beam pro­files which lim­its how well prop­a­ga­tion can be pre­dicted, how­ever by using the well-stud­ied quad-scan tech­nique it is pos­si­ble to ob­tain all of the Twiss pa­ra­me­ters at a point using these pro­files. Ex­per­i­men­tal quad-scans of muon beams have not yet been re­ported, this paper in­tro­duces the quad-scan tech­nique and then goes on to dis­cuss the analy­sis of one such ex­per­i­ment and the re­sults ob­tained, show­ing that such a tech­nique is ap­plic­a­ble in the muon g-2 ex­per­i­ment to ob­tain the Twiss pa­ra­me­ters with­out re­quir­ing in­stal­la­tion of new equip­ment.  
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WEPAF035 Coherent Diffraction Radiation Imaging as an RMS Bunch Length Monitor radiation, FEL, target, detector 1895
 
  • J. Wolfenden, R.B. Fiorito, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • R.B. Fiorito, C.P. Welsch, J. Wolfenden
    The University of Liverpool, Liverpool, United Kingdom
  • T.H. Pacey, T.H. Pacey
    UMAN, Manchester, United Kingdom
  • A.G. Shkvarunets
    UMD, College Park, Maryland, USA
  
  Funding: This work was supported by the EU under Grant Agreement No. 624890 and the STFC Cockcroft Institute core Grant No. ST/G008248/1.
High-res­o­lu­tion bunch length mea­sure­ment is of the ut­most im­por­tance for cur­rent and fu­ture gen­er­a­tions of light sources and linacs. It is also key to the op­ti­mi­sa­tion of the final beam qual­ity in plasma-based ac­cel­er­a­tion. We pre­sent progress in the de­vel­op­ment of a novel RMS bunch length mon­i­tor based on imag­ing the co­her­ent dif­frac­tion ra­di­a­tion (CDR) pro­duced by a non-in­va­sive cir­cu­lar aper­ture. Due to the bunch lengths in­volved, the ra­di­a­tion pro­duced is in the THz range. This has led to the de­vel­op­ment of a novel THz imag­ing sys­tem, which can be ap­plied to low en­ergy elec­tron beams. For high en­ergy beams the imag­ing sys­tem can be used as a sin­gle shot tech­nique. Sim­u­la­tion re­sults show that the pro­file of a CDR image of a beam is sen­si­tive to bunch length and can thus be used as a di­ag­nos­tic. The as­so­ci­ated ben­e­fits of this imag­ing dis­tri­b­u­tion method­ol­ogy over the typ­i­cal an­gu­lar dis­tri­b­u­tion mea­sure­ment are dis­cussed. Plans for ex­per­i­ments con­ducted at the Swiss­FEL (PSI, Switzer­land), along with plans for fu­ture high en­ergy sin­gle shot mea­sure­ments are also pre­sented. 		 
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WEPAF058 Detection of X-Rays and Charged Particles via Detuning of the Microwave Resonator coupling, resonance, monitoring, network 1958
 
  • S.P. Antipov
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • S.V. Kuzikov
    Euclid Beamlabs LLC, Bolingbrook, USA
  • S. Stoupin
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
  
  Funding: DOE SBIR
Crit­i­cally cou­pled mi­crowave res­onator is a finely bal­anced sys­tem, re­flec­tion at the res­o­nance is vir­tu­ally zero. Small changes in di­elec­tric prop­er­ties of res­onator parts de­stroy this bal­ance, small re­flec­tion can be de­tected from the res­onator. This mea­sure­ment is used in elec­tron para­mag­netic res­o­nance stud­ies. In this paper we dis­cuss two ac­cel­er­a­tor - re­lated ap­pli­ca­tions of this tech­nol­ogy. First is re­lated to beam halo mea­sure­ment tak­ing ad­van­tage of high sen­si­tiv­ity of the mi­crowave mea­sure­ment. High en­ergy par­ti­cles cross­ing the di­a­mond in­side of a tuned res­onator in­duce a weak con­duc­tiv­ity in the sens­ing ma­te­r­ial. This small change re­sults in res­onator de­cou­pling pro­vid­ing a sig­nal pro­por­tional to a num­ber of par­ti­cles cross­ing the di­a­mond plate. Sec­ond ap­pli­ca­tion con­sid­ered is the x-ray flux mon­i­tor­ing. In this case it is x-ray in­duced pho­to­con­duc­tiv­ity which al­ters res­onator cou­pling and pro­duces a sig­nal. In­ter­est­ingly, sens­ing di­elec­tric ma­te­r­ial em­bed­ded in a res­onator can be a di­a­mond or kap­ton win­dow, re­frac­tive lens or part of a sil­i­con mono­chro­ma­tor. Thus an in­evitable x-ray ab­sorp­tion on op­ti­cal el­e­ments of the beam­line is used to mon­i­tor x-ray flux on­line. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF058  
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WEPAF064 Dependable Implementation of the Beam Interlock Mechanism in CERN Power Converter Controllers controls, operation, software, interface 1975
 
  • M. Di Cosmo, Q. King, R. Murillo-Garcia, D. Nisbet, B. Todd
    CERN, Geneva, Switzerland
  
  At CERN a Beam In­ter­lock Sys­tem (BIS) pro­tects ac­cel­er­a­tors from ac­ci­den­tal and un­con­trolled re­lease of beam en­ergy, avoid­ing ma­chine down­time. Through­out the ac­cel­er­a­tor com­plex nu­mer­ous crit­i­cal sub­sys­tems, in­clud­ing power con­vert­ers, in­ter­act with the BIS in­di­cat­ing their readi­ness for op­er­a­tion with beam. Power con­vert­ers play a vital role in es­tab­lish­ing op­er­a­tional con­di­tions, and an un­mit­i­gated power con­verter mal­func­tion could lead to dam­age to the ma­chine. For ex­am­ple a bend­ing mag­net con­verter set at an in­cor­rect cur­rent would re­sult in an in­cor­rect field strength, and beam pass­ing through this may im­pact and dam­age the ma­chine. A fast and de­pend­able Beam In­ter­lock Mech­a­nism is re­quired be­tween power con­vert­ers and BIS, ver­i­fy­ing that volt­age and cur­rent lev­els are within tol­er­ances. This paper de­scribes the de­sign and re­al­i­sa­tion of the Beam In­ter­lock Mech­a­nism, based on CERN's Func­tion Gen­er­a­tor Con­troller (FGC), the cen­tral pro­cess­ing unit power con­verter con­trol. Par­tic­u­lar em­pha­sis is placed on the sys­tem ar­chi­tec­ture re­quired to as­sure the in­tegrity of the power con­verter pa­ra­me­ters, and the pro­tec­tion of the CERN ac­cel­er­a­tor com­plex.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF064  
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WEPAF070 Commissioning of Beam Instrumentation at the CERN AWAKE Facility After Integration of the Electron Beam Line electron, proton, plasma, laser 1993
 
  • I. Gorgisyan, C. Bracco, S. Burger, S. Döbert, S.J. Gessner, E. Gschwendtner, L.K. Jensen, S. Jensen, S. Mazzoni, D. Medina, K. Pepitone, L. Søby, F.M. Velotti, M. Wendt
    CERN, Geneva, Switzerland
  • M. Cascella, S. Jolly, F. Keeble, M. Wing
    UCL, London, United Kingdom
  • V.A. Verzilov
    TRIUMF, Vancouver, Canada
  
  The Ad­vanced Pro­ton Dri­ven Plasma Wake­field Ac­cel­er­a­tion Ex­per­i­ment (AWAKE) is a pro­ject at CERN aim­ing to ac­cel­er­ate an elec­tron bunch in a plasma wake­field dri­ven by a pro­ton bunch*. The plasma is in­duced in a 10 m long Ru­bid­ium vapour cell using a pulsed Ti:Sap­phire laser, with the wake­field formed by a pro­ton bunch from the CERN SPS. A 16 MeV elec­tron bunch is si­mul­ta­ne­ously in­jected into the plasma cell to be ac­cel­er­ated by the wake­field to en­er­gies in GeV range over this short dis­tance. After suc­cess­ful runs with the pro­ton and laser beams, the elec­tron beam line was in­stalled and com­mis­sioned at the end of 2017 to pro­duce and in­ject a suit­able elec­tron bunch into the plasma cell. To achieve the goals of the ex­per­i­ment, it is im­por­tant to have re­li­able beam in­stru­men­ta­tion mea­sur­ing the var­i­ous pa­ra­me­ters of the pro­ton, elec­tron and laser beams such as trans­verse po­si­tion, trans­verse pro­file as well as tem­po­ral syn­chro­niza­tion. This con­tri­bu­tion pre­sents the sta­tus of the beam in­stru­men­ta­tion in AWAKE, in­clud­ing the new in­stru­ments in­cor­po­rated into the sys­tem for mea­sure­ments with the elec­tron beam line, and re­ports on the per­for­mance achieved dur­ing the AWAKE runs in 2017.
* Gschwendtner E., et al. "AWAKE, the Advanced Proton Driven Plasma Wakefield Experiment at CERN", NIM A 829 (2016)76-82 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF070  
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WEPAF079 A Smart Framework for the Availability and Reliability Assessment and Management of Accelerators Technical Facilities operation, framework, GUI, controls 2024
 
  • L. Serio, A. Castellano, U. Gentile
    CERN, Geneva, Switzerland
  • F. Antonello, P. Baraldi, E. Zio
    Politecnico di Milano, Milan, Italy
  
  CERN op­er­ates and main­tains a large and com­plex tech­ni­cal in­fra­struc­ture serv­ing the ac­cel­er­a­tor com­plex and ex­per­i­ments de­tec­tors. A per­for­mance as­sess­ment and en­hance­ment frame­work based on data min­ing, ar­ti­fi­cial in­tel­li­gence and ma­chine-learn­ing al­go­rithms is under de­vel­op­ment with the ob­jec­tive of struc­tur­ing, col­lect­ing and an­a­lyz­ing sys­tems and equip­ment op­er­a­tion and fail­ure data, to guide the iden­ti­fi­ca­tion and im­ple­men­ta­tion of ad­e­quate cor­rec­tive, pre­ven­tive and con­sol­i­da­tion in­ter­ven­tions. The frame­work is de­signed to col­lect and struc­ture the data, iden­tify and an­a­lyze the as­so­ci­ated dri­ving events. It de­vel­ops dy­nam­i­cally func­tional de­pen­den­cies and logic trees, de­scrip­tive and pre­dic­tive mod­els to sup­port op­er­a­tion and main­te­nance ac­tiv­i­ties to im­prove the re­li­a­bil­ity and avail­abil­ity of the in­stal­la­tions. To val­i­date the per­for­mance of the frame­work and qual­ity of the al­go­rithms sev­eral case stud­ies are being car­ried out. We re­port on the de­sign, im­ple­men­ta­tion and on the pre­lim­i­nary re­sults in­ferred on his­tor­i­cal and live stream data from CERN's tech­ni­cal in­fra­struc­ture. Pro­posal for the full de­ploy­ment and ex­pected long-term ca­pa­bil­i­ties will also be dis­cussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF079  
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WEPAF082 A Systematic Analysis of the Prompt Dose Distribution at the Large Hadron Collider operation, radiation, luminosity, proton 2036
 
  • O. Stein, K. Bilko, M. Brugger, S. Danzeca, D. Di Francesca, R. Garcia Alia, Y. Kadi, G. Li Vecchi, C. Martinella
    CERN, Geneva, Switzerland
  
  Dur­ing the op­er­a­tion of the Large Hadron Col­lider (LHC) the con­tin­u­ous par­ti­cle losses cre­ate a mixed par­ti­cle ra­di­a­tion field in the LHC tun­nel and the ad­ja­cent cav­erns. Ex­posed elec­tron­ics and ac­cel­er­a­tor com­po­nents show dose de­pen­dent ac­cel­er­ated aging ef­fects. In order to achieve an op­ti­mal life­time as­so­ci­ated to ra­di­a­tion dam­age, the po­si­tion of the equip­ment is cho­sen in de­pen­dency of the am­pli­tude of the ra­di­a­tion fields. Based on the con­tin­u­ous analy­sis of the data from more than 3900 ion­i­sa­tion cham­ber beam loss mon­i­tors the evo­lu­tion of the ra­di­a­tion lev­els is mon­i­tored dur­ing the ac­cel­er­a­tor op­er­a­tion. Nor­mal­is­ing the ra­di­a­tion fields with ei­ther the in­te­grated lu­mi­nos­ity or the in­te­grated in­ten­si­ties al­lows ex­trap­o­lat­ing the ra­di­a­tion lev­els of fu­ture ac­cel­er­a­tor op­er­a­tion. In this paper, the gen­eral ra­di­a­tion lev­els in the arcs and the in­ser­tion re­gions at the LHC and their evo­lu­tion will be pre­sented. The changes in the prompt dose dis­tri­b­u­tion along the LHC be­tween the op­er­a­tion in 2016 and 2017 will be dis­cussed. The im­pact of dif­fer­ent ac­cel­er­a­tor set­tings on the local dose dis­tri­b­u­tion will be ad­dressed as well.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF082  
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WEPAK007 Slow Extraction Spill Characterization From Micro to Milli-Second Scale extraction, power-supply, resonance, betatron 2095
 
  • R. Singh, P. Boutachkov, P. Forck, S. Sorge, H. Welker
    GSI, Darmstadt, Germany
  
  This con­tri­bu­tion deals with the topic of slow ex­trac­tion spill qual­ity char­ac­ter­i­za­tion based on the mea­sure­ments per­formed at GSI SIS-18. The sen­si­tiv­ity of the spill to power sup­ply rip­ples are stud­ied by in­tro­duc­ing ex­ter­nal rip­ples. An es­ti­mate of sources of in­her­ent power sup­ply rip­ples along with rip­ple mag­ni­tude are thus ob­tained. Spill char­ac­ter­i­za­tion in time and fre­quency do­main are dis­cussed and ex­em­pli­fied by a typ­i­cal spill and the dif­fer­ences from an ideal or Pois­son spill. An ap­pro­pri­ate spill char­ac­ter­i­za­tion aims to pro­vide a suit­able ab­strac­tion for com­mu­ni­ca­tion about the spill qual­ity re­quire­ments be­tween ac­cel­er­a­tor op­er­a­tions and users.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAK007  
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WEPAL006 Experimental Study of a Differential Beam Intensity Monitoring for the CIADS LINAC pick-up, linac, monitoring, machine-protect 2155
 
  • Z.P. Xie, Y.K. Ding, J. Liang
    Hohai University, Nanjing, People's Republic of China
  • Y. He, Z.J. Wang, J.X. Wu, Y. Zhang
    IMP/CAS, Lanzhou, People's Republic of China
  
  Funding: Work supported by the National Natural Science Foundation of China (Grant No. 91026001) and the Fundamental Research Funds for the Chinese Central Universities
A BPM based beam loss mon­i­tor­ing scheme for the China ini­tia­tive ac­cel­er­a­tor dri­ven sub­crit­i­cal (CIADS) fa­cil­ity has been pro­posed for the MEBT sec­tion of its high power Linac. In this scheme, a dif­fer­en­tial beam mon­i­tor­ing al­go­rithm is uti­lized that re­lies on beam in­ten­sity mea­sure­ments using BPM elec­trodes. Dis­cus­sions of the ex­per­i­men­tal re­sults for the scheme are pre­sented. Fur­ther ex­per­i­ments have been per­formed with some promis­ing re­sults. This paper de­scribes the ex­per­i­men­tal re­sults with some analy­ses on mea­sure­ment er­rors of the sys­tem. The pro­posed phys­i­cal de­sign of this sys­tem is de­scribed and fur­ther de­vel­op­ment is pre­sented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL006  
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WEPAL011 iPipe: An Innovative Fiber Optic Monitoring System for Beam Induced Heating on Accelerator Pipes monitoring, radiation, operation, detector 2166
 
  • F. Fienga, S. Buontempo, M.R. Masullo
    INFN-Napoli, Napoli, Italy
  • A. Ball, N. Beni, B. Salvant, W. Zeuner
    CERN, Geneva, Switzerland
  • G. Breglio, A. Irace
    University of Napoli Federico II, Napoli, Italy
  • Z. Szillasi
    ATOMKI, Debrecen, Hungary
  • V.G. Vaccaro
    Naples University Federico II and INFN, Napoli, Italy
  
  The iPipe pro­ject con­sists in the in­stru­men­ta­tion, with Fiber Bragg Grat­ing sen­sors (FBGs), of the beam pipe of the CMS ex­per­i­ment, which is part of the LHC. Being spec­trally en­coded, the FBGs are not sen­si­tive to elec­tro­mag­netic in­ter­fer­ence and broad­band-ra­di­a­tion-in­duced losses. These char­ac­ter­is­tics allow to re­al­ize long dis­tance punc­tual sens­ing sys­tems, ca­pa­ble to op­er­ate in harsh en­vi­ron­ments like the un­der­ground ex­per­i­men­tal and ac­cel­er­a­tor fa­cil­i­ties at CERN. The iPipe se­cures the mea­sure­ment of any de­for­ma­tion in­duced on the cen­tral beam pipe by any mo­tion in the CMS de­tec­tor due to el­e­ment dis­place­ment or to mag­netic field in­duced de­for­ma­tions. More­over, the iPipe FBG tem­per­a­ture sen­sors rep­re­sent a unique so­lu­tion to mon­i­tor the beam pipe ther­mal be­hav­ior dur­ing the var­i­ous op­er­a­tional and main­te­nance phases. This paper re­ports the use of the iPipe to mea­sure the beam in­duced heat­ing on the CMS vac­uum cham­ber through­out 2016 and 2017. A first com­par­i­son be­tween the mea­sure­ments and the heat load pre­dicted from beam in­duced RF heat­ing due to the cou­pling im­ped­ance of the CMS pipe is also re­ported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL011  
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WEPAL018 A Non-destructive 2D Profile Monitor Using a Gas Sheet electron, proton, linac, target 2190
 
  • N. Ogiwara, Y. Namekawa
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • M. Fukuda, K. Hatanaka, T. Shima, K. Takahisa
    RCNP, Osaka, Japan
  • Y. Hikichi, J. Kamiya, M. Kinsho
    JAEA/J-PARC, Tokai-mura, Japan
  • Y. Hori
    KEK, Tokai, Ibaraki, Japan
  
  We are de­vel­op­ing a non-de­struc­tive and fast-re­sponse beam pro­file mon­i­tor using a dense gas sheet tar­get. To make a gas sheet, we use the beam­ing ef­fect, which is well known in vac­uum sci­ence and tech­nol­ogy. The emit­ted mol­e­cules through a long rec­tan­gu­lar chan­nel, which has a very small ratio of the gap to the width, are forced to con­cen­trate on a plane. The gas sheet with a thick­ness of 1.5 mm and the den­sity of 2×10-4 Pa was eas­ily gen­er­ated by the com­bi­na­tion of the deep slit and the thin slit. Here, the gas sheet was pro­duced by the deep slit, and the shape of the sheet was im­proved by the thin slit. The use­ful­ness of this mon­i­tor was shown by the fol­low­ing ex­per­i­ments: 1) For the elec­tron beam of 30 keV with a di­am­e­ter greater than 0.35 mm, the po­si­tion and the two-di­men­sional pro­files were well mea­sured using the gas sheet. 2) Then the pro­files of the 10 and 400 MeV pro­ton beam with a cur­rent of sev­eral mi­croam­peres were well mea­sured, too. 3) Re­cently, the pro­files of the 400 MeV H− ion beams in J-PARC linac were mea­sured.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL018  
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WEPAL023 Pulsed Operation at MAMI with High Beam Loading beam-losses, operation, klystron, beam-loading 2206
 
  • M. Dehn, K. Aulenbacher, F. Fichtner, P. Jennewein, W. Klag, H.-J. Kreidel, J.R. Röthgen
    IKP, Mainz, Germany
  
  Funding: Work supported by DFG (CRC 1044) and the German federal state of Rhineland-Palatinate
The Mainz Mi­cro­tron Ac­cel­er­a­tor (MAMI) is a mi­cro­tron cas­cade which is nor­mally op­er­ated CW for par­ti­cle physics ex­per­i­ments. For cer­tain in­ves­ti­ga­tions it is nec­es­sary to use a pulsed beam (macro pulses, sev­eral mil­lisec­onds). Up to now this pulsed mode can only be ap­plied if the beam load­ing for the ac­cel­er­at­ing RF struc­tures is neg­li­gi­ble. To achieve higher pulse in­ten­si­ties the ac­cel­er­a­tor RF in­fra­struc­ture needs to be equipped with feed-for­ward tech­niques to com­pen­sate for the ex­pected beam load­ing. To mon­i­tor beam losses the ma­chine pro­tec­tion sys­tem at MAMI needs to be ex­tended to be able to lo­cal­ize fast oc­cur­rences of beam losses. This paper will pre­sent the pos­si­bil­i­ties being in­ves­ti­gated to allow pulsed op­er­a­tion of MAMI within the near fu­ture. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL023  
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WEPAL024 High Precision Beam Parameter Stabilization for P2 at MESA cavity, electron, controls, resonance 2209
 
  • R.F.K. Kempf, J. Diefenbach
    IKP, Mainz, Germany
  • K. Aulenbacher
    HIM, Mainz, Germany
  
  Funding: Cluster of Excellence PRISMA (EXC 1098/2014) German Research Foundation DFG (GRK 2128)
The ex­per­i­ment P2 will mea­sure the weak mix­ing angle with an all-time high pre­ci­sion via elec­tron-pro­ton scat­ter­ing. The mea­sured physics asym­me­try and its un­cer­tainty has to be cor­rected by the ap­pa­ra­tus' asym­me­try, which is gen­er­ated by he­lic­ity cor­re­lated fluc­tu­a­tions of the beam pa­ra­me­ters po­si­tion, angle, in­ten­sity and en­ergy. This Poster will de­scribe how the high pre­ci­sion of 0.1 ppb of the par­ity vi­o­lat­ing asym­me­try can be pro­vided by the high pre­ci­sion mea­sure­ments of the pa­ra­me­ters po­si­tion, angle and in­ten­sity. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL024  
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WEPAL034 Bunch Length Measurements Using Coherent Smith-Purcell Radiation With Several Gratings at CLIO booster, radiation, detector, laser 2239
 
  • N. Delerue, S. Jenzer, V. Khodnevych, A. Migayron
    LAL, Orsay, France
  • J.P. Berthet, N. Jestin, J.-M. Ortega, R. Prazeres
    CLIO/ELISE/LCP, Orsay, France
  
  Funding: Financially supported by the Université Paris-Sud (programme "attractivité"), by the French ANR (contract ANR-12-JS05-0003-01) and by IN2P3.
Co­her­ent Smith Pur­cell ra­di­a­tion al­lows the mea­sure­ment of a beam lon­gi­tu­di­nal pro­file through the study of the emis­sion spec­trum of the ra­di­a­tion emit­ted when a grat­ing is brought close from the beam. In order to in­crease the dy­namic range of our mea­sure­ments we have used sev­eral grat­ings and we re­port on the mea­sured bunch form fac­tor using this tech­nique. We re­port on these mea­sure­ments and on the back­ground re­jec­tion used. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL034  
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WEPAL041 FPGA Based Optical Phase Control for Coherent Laser Pulse Stacking cavity, controls, FPGA, laser 2265
 
  • Y. Yang, L.R. Doolittle, Q. Du, G. Huang, W. Leemans, R.B. Wilcox, T. Zhou
    LBNL, Berkeley, California, USA
  • A. Galvanauskas
    University of Michigan, Ann Arbor, Michigan, USA
  
  Co­her­ent tem­po­ral pulse stack­ing com­bines the en­ergy from a train of pulses into one pulse through a se­ries of op­ti­cal cav­i­ties. To sta­bi­lize the out­put en­ergy, the cav­ity roundtrip phases must be pre­cisely locked to par­tic­u­lar val­ues. Lever­ag­ing the LLRF ex­per­tise we have for con­ven­tional ac­cel­er­a­tors, a FPGA-based con­trol sys­tem has been de­vel­oped for op­ti­cal cav­ity phase con­trol. A phase mea­sure­ment method, ''Mod­u­lated Im­pulse Re­sponse'', has been de­vel­oped and im­ple­mented on FPGA. An ex­per­i­ment demon­strated that it can mea­sure and lock the op­ti­cal phases of four stack­ing cav­i­ties, lead­ing to com­bi­na­tion of 25 pulses into one pulse with 1.5 % RMS sta­bil­ity over 30 hours.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL041  
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WEPAL066 Determination of RF Resonator Axis Inclination to Beam Axis in Electron-Positron Storage Ring resonance, kicker, electron, positron 2330
 
  • Leshenok D. Leshenok
    NSU, Novosibirsk, Russia
  • S.A. Nikitin
    BINP SB RAS, Novosibirsk, Russia
  
  We pro­posed and tested the method that al­lows ob­tain­ing of an upper limit for an angle of the RF res­onator axis in­cli­na­tion rel­a­tive to a beam axis. Such dis­tur­bance gives an ad­di­tional con­tri­bu­tion to sep­a­ra­tion of elec­tron and positron or­bits due to ac­tion of the trans­verse com­po­nent of the elec­tric field. In the hor­i­zon­tal plane, this ef­fect can lead to in­crease of the dif­fer­ence be­tween elec­trons and positrons spin pre­ces­sion fre­quen­cies in a stor­age mono-ring col­lider. This ef­fect can play a great role in FCC. At the an­gu­lar dis­tur­bance of axis in the cer­tain VEPP-4M RF res­onators ~10-3 rad, the dif­fer­ence be­tween the spin fre­quen­cies is about 10-8. Our method is based on res­o­nant ex­ci­ta­tion of be­ta­tron os­cil­la­tions using phase mod­u­la­tion of the mas­ter os­cil­la­tor of the RF sys­tem. The max­i­mal am­pli­tude of the en­forced os­cil­la­tions is mea­sured by the count­ing rate of the VEPP-4M Tou­schek po­larime­ter scin­til­la­tion coun­ters. Com­par­i­son of the ob­tained re­sults with the data of the spe­cial cal­i­bra­tion ex­per­i­ment al­lows es­ti­mat­ing the value of the in­cli­na­tion angle. In this cal­i­brated ex­per­i­ment the be­ta­tron os­cil­la­tions ex­cite using the VEPP-4M kicker.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL066  
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WEPMF009 Influence of Argon-Ion Irradiation on Field Emission from Polycrystalline Cu and Large-Grain NB Surfaces radiation, niobium, cavity, vacuum 2384
 
  • S. Soykarci
    University of Wuppertal, Wuppertal, Germany
  • D. Lützenkirchen-Hecht, V. Porshyn, P. Serbun
    Bergische Universität Wuppertal, Wuppertal, Germany
  
  Funding: This work is funded by the BMBF project 05H15PXRB1.
In the pre­sent work, sys­tem­atic in­ves­ti­ga­tions of the en­hanced field emis­sion (EFE) from poly­crys­talline cop­per and large grain nio­bium sur­faces be­fore and after ar­gon-ion ir­ra­di­a­tion with an en­ergy of 5 keV were per­formed with a vari­a­tion of the ir­ra­di­a­tion time. Re­sults show that the sup­pres­sion of the EFE might be achiev­able. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF009  
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WEPMF010 Laser Treatment of Niobium Surface for SRF Aplications laser, cavity, niobium, electron 2387
 
  • V. Porshyn, D. Lützenkirchen-Hecht, P. Serbun
    Bergische Universität Wuppertal, Wuppertal, Germany
  • H. Bürger, S. Soykarci
    University of Wuppertal, Wuppertal, Germany
  
  Funding: The research was funded by the German Federal Ministry of Education and Research (BMBF) under project number 05H15PXRB1.
We re­port on a laser sur­face treat­ment of high pu­rity nio­bium (110) sin­gle crys­tals. Typ­i­cal sur­face de­fects like scratches, pits, sharp rims and holes were elim­i­nated by a fo­cused pulsed ns-laser beam. A laser flu­ence of about 0.68 J/cm2 and 40 - 80 pulses per spot were re­quired to in­duce well de­tectable sur­face mod­i­fi­ca­tions. The remelted sur­face was suf­fi­ciently smooth, but ex­hib­ited also a num­ber of wave struc­tures. Thus, the sur­face rough­ness slightly in­creased with in­creas­ing num­ber of pulses. Fi­nally, boil­ing traces and μm-deep ab­la­tion were ob­served and stud­ied as well. Local field elec­tron emis­sion mea­sure­ments showed no emis­sion up to 700 MV/m from a mod­er­ate remelted area below the boil­ing point. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF010  
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WEPMF032 Experimental Studies on Secondary Electron Emission Characteristics for Chamber Materials of Accelerators electron, detector, vacuum, neutron 2425
 
  • Y. Jiao, Z. Duan, W.B. Liu, Y.D. Liu
    IHEP, Beijing, People's Republic of China
  • Liu. S. Liu
    Institute of High Energy Physics (IHEP), People's Republic of China
  • P.C. Wang
    DNSC, Dongguan, People's Republic of China
  
  Funding: National Natural Science Foundation of China (11275221) and Key Laboratory Foundation of Particle Acceleration Physics &Technology (Y5294106TD)
Sec­ondary elec­tron emis­sion (SEE) of sur­face is ori­gin of mul­ti­pact­ing ef­fect which could se­ri­ously de­te­ri­o­rate beam qual­ity and even per­turb the nor­mal op­er­a­tion of par­ti­cle ac­cel­er­a­tors. Ex­per­i­men­tal mea­sure­ments on sec­ondary elec­tron yield (SEY) on dif­fer­ent ma­te­ri­als and coat­ing have been de­vel­oped in many ac­cel­er­a­tor lab­o­ra­tory. In fact, the SEY is just one pa­ra­me­ter of sec­ondary elec­tron emis­sion char­ac­ter­is­tics which in­clude spa­tial and en­ergy dis­tri­b­u­tion of emit­ted elec­trons. A novel ex­per­i­men­tal ap­pa­ra­tus was set up in China Spal­la­tion Neu­tron Source (CSNS) and in­no­v­a­tive mea­sure­ment meth­ods were ap­plied to ob­tain the whole char­ac­ter­is­tics of SEE. With some tra­di­tional ac­cel­er­a­tor cham­ber ma­te­ri­als such as Cu, Al, TiN, SEY de­pen­dence on pri­mary elec­tron en­ergy and beam in­jec­tion angle, spa­tial and en­ergy dis­tri­b­u­tion of emit­ted sec­ondary elec­trons were achieved with this mea­sure­ment ap­pa­ra­tus. This con­tri­bu­tion also tries to give all the ex­per­i­men­tal re­sults a rea­son­able the­o­ret­i­cal analy­sis. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF032  
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WEPMF039 Experimental Results on the Field and Frequency Dependence of the Surface Resistance of Niobium Cavities cavity, niobium, vacuum, electron 2451
 
  • P.N. Koufalis, M. Liepe, J.T. Maniscalco, T.E. Oseroff
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  We in­ves­ti­gate the field and fre­quency de­pen­dence of the sur­face re­sis­tance of sin­gle-cell nio­bium cav­i­ties as a func­tion of sur­face treat­ment at 1.3, 2.6, and 3.9 GHz. The sur­face re­sis­tance is bro­ken down into two parts: the tem­per­a­ture-in­de­pen­dent resid­ual re­sis­tance and the tem­per­a­ture-de­pen­dent BCS re­sis­tance. While the low-field BCS re­sis­tance is known to vary qua­drat­i­cally with fre­quency, the exact de­pen­dence of the BCS and resid­ual re­sis­tances on field at higher fre­quen­cies are im­por­tant top­ics for fur­ther in­ves­ti­ga­tion. We offer re­sults on a sys­tem­atic ex­per­i­men­tal study of the resid­ual and BCS re­sis­tance as a func­tion of fre­quency and field for clean nio­bium and high-tem­per­a­ture ni­tro­gen-doped nio­bium.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF039  
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WEPMF041 Insights into the Role of C, N, and O Introduced by Low Temperature Baking on Niobium Cavity Performance cavity, niobium, ECR, superconductivity 2455
 
  • P.N. Koufalis, M. Liepe
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Pre­vi­ous ex­per­i­ments have shown that in­tro­duc­ing ni­tro­gen gas dur­ing low tem­per­a­ture bakes (120-160 C) of nio­bium cav­i­ties in­tro­duces C, N, and O im­pu­ri­ties to the first 10-100 nm of the sur­face. This new treat­ment re­sults in higher qual­ity fac­tors and even 'anti-Q-slope' in some cases. How­ever, it is not en­tirely clear the role that each of these im­pu­ri­ties plays in the per­for­mance en­hance­ment of the cav­i­ties. It has been sug­gested that in­ter­sti­tial N within the first few nm of the sur­face is solely re­spon­si­ble for the ob­served en­hance­ment, but lit­tle work has been done on the role of C and O. Be­cause both C and O are abun­dant in much higher quan­ti­ties than N near the sur­face, it is im­por­tant to un­der­stand whether they are ben­e­fi­cial or detri­men­tal to cav­ity per­for­mance. We pro­vide fur­ther in­sight into the ef­fects of C and O on cav­ity per­for­mance by bak­ing in an am­bi­ent at­mos­phere rich in CO2 as op­posed to N2.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF041  
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WEPMF046 Modeling of the Frequency and Field Dependence of the Surface Resistance of Impurity-Doped Niobium cavity, niobium, ECR, SRF 2471
 
  • J.T. Maniscalco, P.N. Koufalis, M. Liepe
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  The anti-Q-slope, a field-de­pen­dent de­crease in sur­face re­sis­tance ob­served in im­pu­rity-doped nio­bium, has been in­ves­ti­gated ex­ten­sively in 1.3 GHz cav­i­ties. New early re­search into this ef­fect has re­cently been per­formed at higher and lower fre­quen­cies, re­veal­ing an ad­di­tional de­pen­dence on fre­quency: the anti-Q-slope is stronger at higher fre­quen­cies and weaker at lower fre­quen­cies. Sev­eral mod­els have been pro­posed to ex­plain the anti-Q-slope, with vary­ing suc­cess in this new fre­quency-de­pen­dent regime. In this work, we an­a­lyze re­cent ex­per­i­men­tal data from a low-tem­per­a­ture-doped 1.3 GHz cav­ity and a high-tem­per­a­ture ni­tro­gen-doped 2.6 GHz cav­ity and dis­cuss the im­pli­ca­tions of these re­sults on the pro­posed mod­els.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF046  
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WEPMF057 PETRA III Vacuum System - Experiences from the First Decade of Operation vacuum, operation, radiation, photon 2499
 
  • L. Lilje, R. Bospflug, N. Plambeck
    DESY, Hamburg, Germany
  
  In 2008 the con­struc­tion of the PETRA III vac­uum sys­tem started. A year later the first pho­tons were de­liv­ered to ini­tial ex­per­i­ments and in 2010 the user op­er­a­tion started. In this paper the op­er­a­tion of the vac­uum sys­tem will be re­viewed. Some of the lessons learned in the ini­tial phase will be pre­sented as well as the main up­grades since then. By now the vac­uum sys­tem has shown a very high re­li­a­bil­ity and shows no sig­nif­i­cant im­pact on the avail­abil­ity of the ma­chine.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF057  
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WEPMF071 Dynamic Testing and Characterization of Advanced Materials in a New Experiment at CERN HiRadMat Facility target, damping, site, proton 2534
 
  • A. Bertarelli, C. Accettura, E. Berthomé, L. Bianchi, F. Carra, C. Fichera, M.I. Frankl, G. Gobbi, P. Grosclaude, M. Guinchard, A. Lechner, M. Pasquali, S. Redaelli, E. Rigutto, O. Sacristan De Frutos
    CERN, Geneva, Switzerland
  • Ph. Bolz, P. Simon
    GSI, Darmstadt, Germany
  • T.R. Furness
    University of Huddersfield, Huddersfield, United Kingdom
  • J. Guardia Valenzuela
    Universidad de Zaragoza, Zaragoza, Spain
  • P. Mollicone, M. Portelli
    UoM, Msida, Malta
  
  Funding: This work has received funding from the European Union's Horizon 2020 Research and Innovation programme under Grant Agreement No 730871.
An in­no­v­a­tive and com­pre­hen­sive ex­per­i­ment (named "Mul­ti­mat") was suc­cess­fully car­ried out at CERN Hi­Rad­Mat fa­cil­ity on 18 dif­fer­ent ma­te­ri­als rel­e­vant for Col­li­ma­tors and Beam In­ter­cept­ing De­vices. Ma­te­r­ial sam­ples, tested under high in­ten­sity pro­ton pulses of 440 GeV/c, ex­ceed­ing the en­ergy den­sity ex­pected in HL-LHC, ranged from very light car­bon foams to tung­sten heavy al­loys, in­clud­ing novel com­pos­ites as graphite/car­bides and metal/di­a­mond with­out and with thin-film coat­ings. Ex­per­i­men­tal data were ac­quired re­ly­ing on ex­ten­sive in­te­grated in­stru­men­ta­tion (strain gauges, tem­per­a­ture sen­sors, ra­di­a­tion-hard cam­era) and on laser Doppler vi­brom­e­ter. This al­lows in­ves­ti­gat­ing rel­a­tively un­ex­plored and fun­da­men­tal phe­nom­ena as dy­namic strength, in­ter­nal en­ergy dis­per­sion, non­lin­ear­i­ties due to in­elas­tic­ity and in­ho­mo­gene­ity, strength and de­lam­i­na­tion of coat­ings and sur­faces. By bench­mark­ing so­phis­ti­cated nu­mer­i­cal sim­u­la­tions against these re­sults, it is pos­si­ble to es­tab­lish or up­date ma­te­r­ial con­sti­tu­tive mod­els, which are of para­mount im­por­tance for the de­sign of de­vices ex­posed to in­ter­ac­tion with par­ti­cle beams in high en­ergy ac­cel­er­a­tors such as the HL-LHC or FCC-hh. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF071  
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WEPMF079 Experimental Modal Analysis of Lightweight Structures used in Particle Detectors: Optical non-contact Method laser, detector, operation, GUI 2565
 
  • M. Guinchard, M. Angeletti, F.B. Boyer, A. Catinaccio, C.G. Gargiulo, L.L. Lacny, E.L. Laudi, L.S. Scislo
    CERN, Geneva, Switzerland
  
  CERN's spe­cial­ized struc­tures such as par­ti­cle de­tec­tors are built to have high rigid­ity and low weight, which comes at a cost of their high fragility. Shock and vi­bra­tion is­sues are a key el­e­ment for their suc­cess­ful trans­port, han­dling op­er­a­tions around the CERN in­fra-struc­ture, as well as for their op­er­a­tion un­der­ground. The ex­per­i­men­tal modal analy­sis mea­sure­ment tech­nique is per­formed to val­i­date the Fi­nite El­e­ment Analy­sis in the case of com­plex struc­tures (with ca­bles and sub­struc­ture cou­pling). In the case of light­weight struc­tures, stan­dard con­tact mea­sure­ments based on ac­celerom­e­ters are not pos­si­ble due to the high mass ratio be­tween the ac­celerom­e­ters and the struc­ture it­self. In such a case, the vi­bra­tion of the struc­ture can be cal­cu­lated based on the Doppler shift of the laser beam re­flected off the vi­brat­ing sur­face. This paper de­tails the func­tion­ing and ap­pli­ca­tion of an ad­vanced laser-scan­ning vi­brom­e­try sys­tem, which uti­lizes the fore-men­tioned non-con­tact method. The re­sults of the Ex­per­i­men­tal Modal Analy­sis of se­lected light­weight struc­ture using this in­stru­ment is also pre­sented and dis­cussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF079  
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WEPMF080 Investigation and Estimation of the LHC Magnet Vibrations Induced by HL-LHC Civil Engineering Activities civil-engineering, network, operation, monitoring 2568
 
  • M. Guinchard, M. Cabon, C. Charrondière, K. Develle, P. Fessia, L.L. Lacny, J.A. Osborne, L.S. Scislo, J. Wenninger
    CERN, Geneva, Switzerland
  
  HL-LHC re­quires the ex­ca­va­tion of large un­der­ground in­fra­struc­tures in order to host new equip­ment. The tun­nel shall be ready for in­stal­la­tion for LS3 (2022) and there­fore its con­struc­tion shall take in place in par­al­lel with the LHC ex­ploita­tion. Ef­fect of vi­bra­tions in­duced by civil en­gi­neer­ing ac­tiv­i­ties need to be eval­u­ated in order to take re­quired cor­rec­tive ac­tions. For this pur­pose, sev­eral di­verse mea­sure­ments and ex­per­i­ments have been per­formed in order to es­ti­mate the vi­bra­tion sources and de­ter­mine the vi­bra­tion trans­fer path through the floor and the struc­ture. The trans­fer func­tions from am­pli­tude and phase point of view were de­ter­mined through mo­lasses rock, for both hor­i­zon­tal and ver­ti­cal vi­bra­tions, with ded­i­cated tools and Ex­per­i­men­tal Modal Analy­sis was car­ried out on me­chan­i­cal struc­ture. The cam­paign of mea­sure­ments have been used to con­firm the ef­fect of the sur­face in­duced vi­bra­tion on the cir­cu­lat­ing beam orbit at the res­o­nance fre­quen­cies of the struc­ture. This paper re­views the ad­vanced tech­nique of mea­sure­ments, re­sults and the con­clu­sion about the im­pact of op­er­at­ing civil en­gi­neer­ing ma­chines (road header, hy­draulic ham­mer) dur­ing beam ex­ploita­tion.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF080  
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WEPMF081 Mechanical Strain Measurements Based on Fiber Bragg Grating Down to Cryogenic Temperature - R&D Study and Applications radiation, cryogenics, superconducting-magnet, GUI 2572
 
  • M. Guinchard, A. Bertarelli, L. Bianchi, F.B. Boyer, M. Cabon, M. Calviani, O. Capatina, A. Catinaccio, P. Ferracin, P. Grosclaude
    CERN, Geneva, Switzerland
  
  In re­cent years, op­ti­cal fiber sen­sors have been in­creas­ingly used due to their out­stand­ing per­for­mances. Their ap­pli­ca­tion is prefer­able in case of spe­cial re­quire­ments that ex­clude the ap­pli­ca­tion of con­ven­tional elec­tri­cal sen­sors. The sci­en­tific back­ground of op­ti­cal fiber sen­sors is well de­vel­oped. How­ever, the char­ac­ter­is­tic of sen­sors em­ployed in rather harsh en­vi­ron­ments is often dif­fer­ent from the one de­ter­mined in lab­o­ra­tory con­di­tions or prior to their in­stal­la­tion. In order to achieve long-term sta­ble func­tion­ing and re­li­able mea­sure­ment under se­vere work­ing en­vi­ron­ments, such as those oc­cur­ring at CERN (ra­di­a­tion, cryo­gen­ics, high mag­netic and elec­tri­cal field), a sta­tis­ti­cal mea­sure­ment cam­paign was car­ried out fol­low­ing the in­ter­na­tional stan­dard ISO 5725. The paper de­scribes the on­go­ing study to de­fine the ac­cu­racy of op­ti­cal fiber sen­sors based on Fiber Bragg Grat­ing (FBG) for strain mea­sure­ments, from room tem­per­a­ture down to 4.2 K. It also de­scribes some of the de­mand­ing ap­pli­ca­tions for which op­ti­cal fiber sen­sors have been de­ployed to per­form ex­per­i­men­tal strain mea­sure­ments (e.g. de­tec­tors com­po­nents, high-en­ergy beam tar­gets and dumps, su­per­con­duct­ing mag­nets).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF081  
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WEPMF083 Comparison of Superconducting Septa Topologies and Parameter Space Exploration septum, dipole, shielding, target 2578
 
  • M.G. Atanasov, J.C.C.M. Borburgh, M. Hourican, A. Sanz Ull
    CERN, Geneva, Switzerland
  
  The un­prece­dented en­ergy scale of the FCC poses chal­leng­ing re­quire­ments for its mag­netic el­e­ments in­clud­ing the sep­tum mag­nets for in­jec­tion and ex­trac­tion. With an am­bi­tious tar­get field of 4 T and an ap­par­ent sep­tum thick­ness of only 25 mm, dif­fer­ent su­per­con­duct­ing septa topolo­gies have been in­ves­ti­gated to ex­plore their lim­i­ta­tions. This ar­ti­cle will cover the cur­rently fea­si­ble topolo­gies, amongst which the trun­cated co­sine-theta, the dou­ble trun­cated co­sine-theta, the su­per­con­duct­ing shield (SuShi) and the so called stealth di­pole. A per­for­mance fig­ure of merit will be pro­posed, tak­ing into ac­count the max­i­mum achiev­able mag­netic field, the sep­tum thick­ness and the leak field mag­ni­tude.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF083  
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WEPMF087 LHC Injectors Upgrade Project: Outlook of the Modifications to the Super Proton Synchrotron (SPS) Vacuum System and Impact on the Operation of the Carbon-Coated Vacuum Chambers vacuum, impedance, proton, extraction 2589
 
  • C. Pasquino, G. Bregliozzi, P. Chiggiato, P. Cruikshank, A. Farricker, A. Harrison, J. Perez Espinos, J.A.F. Somoza, M. Taborelli, C. Vollinger
    CERN, Geneva, Switzerland
  
  Aim­ing at dou­bling the beam in­ten­sity and re­duc­ing the beam emit­tance, sig­nif­i­cant mod­i­fi­ca­tions of the LHC and its in­jec­tor chain will take place dur­ing Long Shut­down 2 (LS2), start­ing from 2019. The LIU pro­ject (LHC In­jec­tor Up­grade), in the spe­cific, touches Linac4, the Pro­ton Syn­chro­tron Booster (PSB), the Pro­ton Syn­chro­tron (PS), the Super Pro­ton Syn­chro­tron (SPS) as well as the heavy ion chain. Dur­ing LS2, im­por­tant changes will take place mainly in the Long Straight Sec­tions of the SPS to host a newly con­ceived dump­ing sys­tem, up­graded RF cav­i­ties and up­graded ex­trac­tion chan­nels. Ad­di­tion­ally, the vac­uum cham­bers of the main bend­ing and fo­cus­ing mag­nets as well as vac­uum drifts will be coated with amor­phous car­bon in order to re­duce the dy­namic pres­sure ef­fects in­duced by mul­ti­pact­ing. The mod­i­fi­ca­tions to the dif­fer­ent vac­uum sec­tors will be de­scribed in de­tails as well as the im­pact on op­er­a­tion of amor­phous car­bon coated sec­tors that have been al­ready de­posited.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF087  
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WEPMF090 Upgrade of the CMS Experimental Beam Vacuum During LS2 vacuum, detector, operation, luminosity 2596
 
  • J.S. Sestak, G. Bregliozzi, P. Chiggiato, C. Di Paolo
    CERN, Geneva, Switzerland
  
  Start­ing from De­cem­ber 2018, the Large Hadron Col­lider (LHC) is going to in­ter­rupt its physic op­er­a­tions for more than two years within the pe­riod called sec­ond long shut­down (LS2). The Com­pact Muon So­le­noid (CMS) ex­per­i­ment will un­dergo the biggest up­grade of its ex­per­i­men­tal beam vac­uum sys­tem since the first op­er­a­tions in 2008. The new ex­per­i­men­tal vac­uum lay­out should com­ply with de­mand­ing struc­tural, vac­uum, in­te­gra­tion and physics re­quire­ments. More­over, the new lay­out should be com­pat­i­ble with fore­seen en­gi­neer­ing changes of the de­tec­tor and the ma­chine dur­ing the up­grade phase of High-Lu­mi­nos­ity LHC in LS3. This paper gives an overview of the CMS LS2 ex­per­i­men­tal vac­uum sec­tors up­grades. Both de­sign and pro­duc­tion phase of the new vac­uum lay­out is dis­cussed in de­tail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF090  
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WEPMG002 Beam Dump Facility Target: Design Status and Beam Tests in 2018 target, radiation, operation, simulation 2604
 
  • E. Lopez Sola, O. Aberle, P. Avigni, L. Bianchi, J. Busom, M. Calviani, M. Casolino, J.P.C. Espadanal, M.A. Fraser, S. Girod, B. Goddard, D. Grenier, M. Guinchard, C. Heßler, R. Illan Fiastre, R. Jacobsson, M. Lamont, A. Ortega Rolo, B. Riffaud, G. Romagnoli, L. Zuccalli
    CERN, Geneva, Switzerland
  
  The Beam Dump Fa­cil­ity (BDF) Pro­ject, cur­rently in its de­sign phase, is a pro­posed gen­eral-pur­pose fixed tar­get fa­cil­ity at CERN, ded­i­cated to the Search for Hid­den Par­ti­cles (SHiP) ex­per­i­ment in its ini­tial phase. At the core of the in­stal­la­tion re­sides the tar­get/dump as­sem­bly, whose aim is to fully ab­sorb the high in­ten­sity 400 GeV/c SPS beam and pro­duce charmed mesons. In ad­di­tion to high thermo-me­chan­i­cal loads, the most chal­leng­ing as­pects of the pro­posed in­stal­la­tion lie in very high en­ergy and power den­sity de­po­si­tion that are reached dur­ing op­er­a­tion. In order to val­i­date the de­sign of the BDF tar­get, a scaled pro­to­type is going to be tested dur­ing 2018 in the North Area at CERN, up­stream the ex­ist­ing beryl­lium pri­mary tar­gets. The pro­to­type test­ing under rep­re­sen­ta­tive beam sce­nar­ios will allow hav­ing an in­sight of the ma­te­r­ial re­sponse in an un­prece­dented regime. On­line mon­i­tor­ing and an ex­ten­sive Post Ir­ra­di­a­tion Ex­per­i­men­tal (PIE) cam­paign are fore­seen. The cur­rent con­tri­bu­tion will de­tail the de­sign and han­dling as­pects of the in­no­v­a­tive Tar­get Com­plex as well as the de­sign of the BDF tar­get/dump core and the de­sign and con­struc­tion of the pro­to­type tar­get as­sem­bly.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMG002  
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WEPMK008 In-Depth Analysis of the Vertical Test Results of the Third-Harmonic Cavities for the E-XFEL Injector cavity, FEL, feedback, SRF 2644
 
  • M. Bertucci, A. Bignami, A. Bosotti, J.F. Chen, C.G. Maiano, P. Michelato, L. Monaco, R. Paparella, P. Pierini, D. Sertore
    INFN/LASA, Segrate (MI), Italy
  • C.G. Maiano, P. Pierini
    ESS, Lund, Sweden
  • C. Pagani
    Università degli Studi di Milano & INFN, Segrate, Italy
  
  The re­sults of the ver­ti­cal tests per­formed at LASA on the 3.9 GHz third-har­monic cav­i­ties for the E-XFEL in­jec­tor are here dis­cussed. Analy­sis of ex­per­i­men­tal data al­lows to con­firm that such high fre­quency cav­ity, pre­pared with stan­dard BCP treat­ment and 800°C an­neal­ing treat­ment, suf­fers an in­trin­sic per­for­mance lim­i­ta­tion at around 22 MV/m (@ 2 K) due to a global ther­mal dis­si­pa­tion mech­a­nism. A quan­ti­ta­tive in­ter­pre­ta­tion of the high field Q slope is also pre­sented ac­cord­ing to the lat­est the­o­ret­i­cal mod­els of field-de­pen­dent sur­face re­sis­tance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMK008  
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WEPMK012 Update on Plasma Processing R&D for LCLS-II plasma, cavity, HOM, SRF 2656
 
  • P. Berrutti, A. Grassellino, T.N. Khabiboulline, M. Martinello
    Fermilab, Batavia, Illinois, USA
  • M. Doleans, S.-H. Kim, K.E. Tippey
    ORNL, Oak Ridge, Tennessee, USA
  • D. Gonnella, G. Lanza, M.C. Ross
    SLAC, Menlo Park, California, USA
  
  Funding: Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE
SRF cav­i­ties per­for­mance preser­va­tion is cru­cial, from ver­ti­cal test to ac­cel­er­a­tor op­er­a­tion. Field emis­sion is still one of the main prob­lems to over­come and plasma clean­ing has been proven suc­cess­ful by SNS, in clean­ing field emit­ters and in­creas­ing the work func­tion of Nb. A col­lab­o­ra­tion has been es­tab­lished be­tween FNAL, SLAC and ORNL with the pur­pose of ap­ply­ing plasma pro­cess­ing to LCLS-II cav­i­ties, in order to min­i­mize and over­come field emis­sion with­out af­fect­ing the high Q of N-doped cav­i­ties. The recipe will fol­low the neon-oxy­gen ac­tive plasma adopted at SNS, al­low­ing in-situ pro­cess­ing of cav­i­ties and cry­omod­ules from hy­dro­car­bon con­t­a­m­i­nants. A novel method for plasma ig­ni­tion has been de­vel­oped at FNAL: a plasma glow dis­charge is ig­nited using high order modes to over­come lim­i­ta­tions im­posed by the fun­da­men­tal power cou­pler. The re­sults of ex­per­i­ments on 9-cell LCLS-II cav­ity are pre­sented, along with plasma ig­ni­tion stud­ies. In ad­di­tion the RF sys­tem is shown and N-doped Nb sam­ples stud­ies are dis­cussed. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMK012  
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WEPML002 Design of 650 MHz Tuner for PIP-II Project cavity, interface, simulation, linac 2671
 
  • Y.M. Pischalnikov, S. Cheban, J.C. Yun
    Fermilab, Batavia, Illinois, USA
  
  Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
The Pro­ton Im­prove­ment Plan (PIP) II pro­ject at Fer­mi­lab is a pro­ton dri­ver linac which will use of five dif­fer­ent cav­ity geome­tries in­clud­ing a 650 MHz 5-cell el­lip­ti­cal cav­i­ties that will op­er­ate in RF-pulse mode. De­tun­ing of these cav­i­ties by Lorentz Forces will be large and strongly de­pend of the stiff­ness of the cav­ity's tuner. First pro­to­type tuner built and tested warm [1,2]. Mea­sured stiff­ness of the pro­to­type tuner was below 30kN/mm in­stead of ex­pected from sim­u­la­tion 70kN/mm [2]. Sig­nif­i­cant ef­fort has been in­vested into un­der­stand­ing dis­crep­ancy be­tween sim­u­la­tion and ex­per­i­men­tal data that led to newest tuner de­sign. Up­dated 'dressed cav­ity-he­lium ves­sel-tuner' model pro­vided con­sis­tent re­sults be­tween ANSYS sim­u­la­tions and ex­per­i­ment re­sults. Mod­i­fied tuner de­sign and analy­sis in lim­i­ta­tions for over­all 'cav­ity/tuner sys­tem' stiff­ness will be pre­sented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML002  
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WEPML013 Anti-Q-slope enhancement in high-frequency niobium cavities cavity, ECR, niobium, SRF 2707
 
  • M. Martinello, S. Aderhold, S.K. Chandrasekaran, M. Checchin, A. Grassellino, O.S. Melnychuk, S. Posen, A.S. Romanenko, D.A. Sergatskov
    Fermilab, Batavia, Illinois, USA
  
  N-doped 1.3 GHz nio­bium cav­i­ties showed for the first time the so-called anti-Q-slope, i.e. the in­creas­ing of the Q-fac­tor as a func­tion of the ac­cel­er­at­ing field. It was ver­i­fied that the anti-Q-slope is con­se­quence of the de­creas­ing of the tem­per­a­ture-de­pen­dent com­po­nent of the sur­face re­sis­tance as a func­tion of the field. This trend is op­po­site com­pared to the in­creas­ing of the sur­face re­sis­tance pre­vi­ously ob­served in 1.3 GHz stan­dard (EP, BCP, 120 C baked) nio­bium cav­i­ties. The ef­fect of the dif­fer­ent state-of-the-art sur­face treat­ments on the field de­pen­dence of the sur­face re­sis­tance is stud­ied for 650 MHz, 1.3 GHz, 2.6 GHz and 3.9 Ghz cav­i­ties. This pro­ceed­ing shows that the field de­pen­dence of the tem­per­a­ture-de­pen­dent com­po­nent of the sur­face re­sis­tance has a strong fre­quency de­pen­dence and that the anti-Q-slope may ap­pear even in clean nio­bium cav­i­ties if the res­o­nant fre­quency is high enough, sug­gest­ing new routes to­ward the un­der­stand­ing of the anti-Q-slope ef­fect.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML013  
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WEPML025 Advantages and Challenges of Nb3Sn Superconducting Undulators undulator, site, operation, photon 2734
 
  • A.V. Zlobin, E.Z. Barzi, D. Turrioni
    Fermilab, Batavia, Illinois, USA
  • Y. Ivanyushenkov, I. Kesgin
    ANL, Argonne, Illinois, USA
  
  Funding: This work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
Su­per­con­duct­ing un­du­la­tors (SCUs) em­ploy su­per­con­duct­ing coils, and due to high crit­i­cal cur­rent den­sity in a su­per­con­duc­tor, out­per­form un­du­la­tors based on per­ma­nent mag­nets in terms of the level of mag­netic field. So far, most of the SCUs, in­clud­ing de­vices built at Ad­vanced Pho­ton Source (APS), use Nb-Ti su­per­con­duc­tor. Uti­liza­tion of Nb3Sn con­duc­tor of­fers a pos­si­bil­ity to in­crease the un­du­la­tor field even fur­ther but re­quires to over­come cer­tain chal­lenges that are de­scribed in this paper. Based on ex­pe­ri­ence of de­vel­op­ing Nb3Sn ac­cel­er­a­tor mag­nets at Fermi Na­tional Ac­cel­er­a­tor Lab­o­ra­tory, pos­si­ble so­lu­tions are dis­cussed. The achiev­able field lev­els for Nb3Sn ver­sion of ex­ist­ing APS and the fu­ture APS-Up­grade su­per­con­duct­ing un­du­la­tors are also pre­sented and dis­cussed. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML025  
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WEPML038 Plasma Window as a Pressure Valve for FAIR plasma, cathode, electron, vacuum 2776
 
  • B. F. Bohlender, M. Iberler, J. Jacoby
    IAP, Frankfurt am Main, Germany
  • A. Michel
    Goethe Universität Frankfurt, Frankfurt am Main, Germany
  
  Funding: Funded by BMBF, Ref. No: 05P15 RFRBA and HIC for FAIR
This con­tri­bu­tion shows the progress in the de­vel­op­ment of a plasma win­dow at the in­sti­tute for ap­plied physics at Goethe Uni­ver­sity Frank­furt. A plasma win­dow* is a mem­brane free tran­si­tion be­tween two re­gions of dif­fer­ent pres­sure, en­abling beam trans­mis­sion from a rough vac­uum area (~1 mbar) to a higher pres­sure (up to 1 bar) re­gion on short length scales. In com­par­i­son to dif­fer­en­tial pump­ing stages a length re­duc­tion by a fac­tor of up to 100 is achiev­able, while the ab­sence of a solid mem­brane yields pro­longed op­er­a­tion time. The seal­ing ef­fect is based on the high tem­per­a­ture arc dis­charge sus­tained in a cooled cop­per chan­nel be­tween the pres­sure regimes. Due to a bulk tem­per­a­ture around 10,000K** the vis­cos­ity of the gas is dra­mat­i­cally in­creased, lead­ing to a slower gas flow, en­abling a higher pres­sure gra­di­ent. This con­tri­bu­tion will pre­sent first re­sults re­gard­ing the pres­sure gra­di­ent in de­pen­dence of the dis­charge cur­rent and the aper­ture. Until now, a pres­sure fac­tor around 100 has been es­tab­lished for well over 50 min. This con­tri­bu­tion goes along with the one from Mr. A. Michel, he fo­cuses on the spec­tro­scopic analy­sis of the arc plasma.
*A. Hershcovitch, J. Appl. Phys., AIP Publishing (1995) 78, 5283
**Y.E. Krasik et al., "Plasma Window Characterization", J. Appl. Phys., AIP Publishing (2007) 101, 053305. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML038  
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WEPML072 Gas Permeability Measurement of Graphene Films vacuum, background, neutron, detector 2856
 
  • P.C. Wang, X. Sun
    DNSC, Dongguan, People's Republic of China
  • Liu. S. Liu
    Institute of High Energy Physics (IHEP), People's Republic of China
  • C. Meng, H. Wang, D.H. Zhu
    IHEP, Beijing, People's Republic of China
  
  Graphene has ex­tremely high strength and ther­mal con­duc­tiv­ity, which can pos­si­bly be used for high-power beam win­dow in ac­cel­er­a­tor. In this paper, gas per­me­abil­i­ties of dif­fer­ent graphene films have been mea­sured by the per­me­ation mea­sure­ment fa­cil­ity. Ac­cord­ing to the re­sults, the pos­si­bil­ity of the graphene-made beam win­dows will be dis­cussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML072  
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THXGBE1 6D Beam Measurement, Challenges and Possibilities simulation, rfq, quadrupole, linac 2890
 
  • A.V. Aleksandrov, S.M. Cousineau, A.P. Zhukov
    ORNL, Oak Ridge, Tennessee, USA
  • B.L. Cathey
    ORNL RAD, Oak Ridge, Tennessee, USA
  
  A sys­tem to mea­sure the full 6D beam pa­ra­me­ters (not 3x2D) has been built at the SNS RFQ test stand. Such a mea­sure­ment will allow de­tailed analy­sis of the beam physics from a prop­erly mea­sured input term. This in­vited pro­vides an overview of the prin­ci­ples and de­sign of this sys­tem, and re­ports on sta­tus and re­sults.  
slides icon Slides THXGBE1 [4.471 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THXGBE1  
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THXGBE2 Optical Diagnostics for Extreme Beam Conditions radiation, emittance, diagnostics, electron 2896
 
  • R.B. Fiorito
    The University of Liverpool, Liverpool, United Kingdom
  
  The de­vel­op­ment of sim­ple, fast, pre­cise and ro­bust beam di­ag­nos­tics is ab­solutely nec­es­sary to op­ti­mize the per­for­mance of pre­sent ac­cel­er­a­tors and to sat­isfy the needs of fu­ture ac­cel­er­a­tors, in par­tic­u­lar those with ex-treme prop­er­ties such as high bright­ness FELs and plasma wake-field ac­cel­er­a­tors. This in­vited talk will pre­sent the un­der­ly­ing physics and re­sults from sim­u­la­tion and ex­per­i­ments for a num­ber of ad­vanced op­ti­cal beam di­ag­nos­tics cur­rently under de­vel­op­ment at var­i­ous ac­cel­er­a­tor re-search lab­o­ra­to­ries in­clud­ing ef­forts at the Cock­croft In­sti­tute.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THXGBE2  
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THYGBD2 Results of UFO Dynamics Studies with Beam in the LHC emittance, proton, beam-losses, simulation 2914
 
  • B. Lindstrom, A. Apollonio, P. Bélanger, M. Dziadosz, A.A. Gorzawski, L. K. Grob, E.B. Holzer, A. Lechner, R. Schmidt, M. Valette, D. Valuch, D. Wollmann
    CERN, Geneva, Switzerland
  
  Mi­crom­e­ter sized par­ti­cles en­ter­ing the LHC beam (the so-called Uniden­ti­fied Falling Ob­jects or UFOs) are a known cause of lo­cal­ized beam losses since the be­gin­ning of high in­ten­sity beam op­er­a­tion, how­ever the ori­gin of these par­ti­cles is not fully known. Their ef­fect lim­its LHC avail­abil­ity by caus­ing pre­ma­ture dumps due to ex­ces­sive beam losses and oc­ca­sion­ally even mag­net quenches. This could be­come an im­por­tant lim­i­ta­tion for fu­ture ac­cel­er­a­tors such as the High Lu­mi­nos­ity up­grade of the LHC (HL-LHC) and the Fu­ture Cir­cu­lar Col­lider (FCC). The dy­nam­ics of these UFOs was in­ves­ti­gated in two ded­i­cated ex­per­i­ments. In the first ex­per­i­ment, it was shown that the trans­verse move­ments of these par­ti­cles can be stud­ied by ob­serv­ing bunch-by-bunch losses from bunches with dif­fer­ent hor­i­zon­tal and ver­ti­cal emit­tances. In the sec­ond ex­per­i­ment, UFO-like events around the 16L2 in­ter­con­nect in the LHC, which has seen in­tense UFO ac­tiv­ity in 2017, were stud­ied with the above method. This paper sum­ma­rizes the re­sults of both ex­per­i­ments.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THYGBD2  
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THYGBF3 Challenges of FAIR Phase 0 operation, controls, MMI, storage-ring 2947
 
  • M. Bai, A. Adonin, S. Appel, R. Bär, M.C. Bellachioma, U. Blell, C. Dimopoulou, G. Franchetti, O. Geithner, P. Gerhard, L. Groening, F. Herfurth, R. Hess, R. Hollinger, H.C. Hüther, H. Klingbeil, A. Krämer, S.A. Litvinov, F. Maimone, D. Ondreka, N. Pyka, S. Reimann, A. Reiter, M. Sapinski, B. Schlitt, G. Schreiber, M. Schwickert, D. Severin, R. Singh, P.J. Spiller, J. Stadlmann, M. Steck, R.J. Steinhagen, K. Tinschert, M. Vossberg, G. Walter, U. Weinrich
    GSI, Darmstadt, Germany
  
  After two-year's shut­down, the GSI ac­cel­er­a­tors plus the lat­est ad­di­tion of stor­age ring CRYRING, will be back into op­er­a­tion in 2018 as the FAIR phase 0 with the goal to ful­fill the needs of sci­en­tific com­mu­nity and the FAIR ac­cel­er­a­tors and de­tec­tor de­vel­op­ment. Even though GSI has been well known for its op­er­a­tion of a va­ri­ety of ion beams rang­ing from pro­ton up to ura­nium for multi re­search areas such as nu­clear physics, as­tro­physics, bio­physics, ma­te­r­ial sci­ence, the up­com­ing beam time faces a num­ber of chal­lenges in re-com­mis­sion­ing its ex­ist­ing cir­cu­lar ac­cel­er­a­tors with brand new con­trol sys­tem and up­grade of beam in­stru­men­ta­tions, as well as in ris­ing fail­ures of dated com­po­nents and sys­tems. The cy­cling syn­chro­tron SIS18 has been un­der­go­ing a set of up­grade mea­sures for ful­fill­ing fu­ture FAIR op­er­a­tion, among which many mea­sures will also be com­mis­sioned dur­ing the up­com­ing beam time. This paper pre­sents the high­lights of the chal­lenges such as re-es­tab­lish­ing the high in­ten­sity heavy ion op­er­a­tion as well as par­al­lel op­er­a­tion mode for serv­ing multi users. The sta­tus of prepa­ra­tion in­clud­ing com­mis­sion­ing re­sults will also be re­ported.  
slides icon Slides THYGBF3 [2.948 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THYGBF3  
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THPAF010 Reduction of Coherent Betatron Oscillations Using RF Electric Fields in the Fermilab Muon g-2 Experiment dipole, quadrupole, simulation, betatron 2961
 
  • O. Kim, S. Hacıömeroğlu, Y.I. Kim, Y.K. Semertzidis
    CAPP/IBS, Daejeon, Republic of Korea
  • Y.F. Orlov
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  The Fer­mi­lab Muon g-2 ex­per­i­ment aims to mea­sure the muon anom­alous mag­netic mo­ment with a 140 parts-per-bil­lion pre­ci­sion to in­ves­ti­gate the greater than 3 stan­dard de­vi­a­tion dif­fer­ence be­tween the Stan­dard Model pre­dic­tion and the pre­vi­ous mea­sure­ment by the BNL Muon g-2 ex­per­i­ment. The co­her­ent be­ta­tron os­cil­la­tion (CBO) beam ef­fects must be cor­rected for in the de­cay-positron time spec­tra fits used in high pre­ci­sion muon stor­age ring based anom­alous mag­netic mo­ment mea­sure­ments. This MC sim­u­la­tion study in­di­cates that the ap­pli­ca­tion of radio fre­quency (RF) elec­tric fields to the muon stor­age ring beam can re­duce the CBO am­pli­tude by up to a fac­tor of 10, as well to in­crease the sym­me­try of the beam phase space. This is achieved by cor­rect­ing the mis­matched os­cil­la­tion phases be­tween the high and low mo­men­tum muon pop­u­la­tions by mod­u­lat­ing the muon beam be­ta­tron os­cil­la­tion fre­quen­cies with off-res­o­nance RF fields.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF010  
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THPAF016 3D Tracking Methods in a GEANT4 Environment Through Electrostatic Beamlines simulation, quadrupole, proton, antiproton 2979
 
  • J.R. Hunt, J. Resta-López, V. Rodin, B. Veglia, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • J.R. Hunt, J. Resta-López, V. Rodin, B. Veglia, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: Work supported by the EU under Grant Agreement 721559 and the STFC Cockcroft Institute core Grant No. ST/G008248/1.
Due to the rel­a­tively in­fre­quent use of elec­tro­sta­tic beam­line el­e­ments com­pared with their mag­netic coun­ter­parts, there are few par­ti­cle track­ing codes which allow for the straight­for­ward im­ple­men­ta­tion of such beam­lines. In this con­tri­bu­tion, we pre­sent 3D track­ing meth­ods for beam­lines con­tain­ing elec­tro­sta­tic el­e­ments util­is­ing a mod­i­fied ver­sion of the Geant4 based track­ing code 'G4beam­line'. In 2020 trans­fer lines will begin trans­port­ing ex­tremely low en­ergy (100 keV) an­tipro­ton beams from the Extra Low En­ergy An­tipro­ton (ELENA) ring to the an­ti­mat­ter ex­per­i­ments at CERN. Elec­tro­sta­tic bend­ing and fo­cus­ing el­e­ments have been cho­sen for the beam­lines due to their mass in­de­pen­dence and fo­cus­ing ef­fi­ciency in the low en­ergy regime. These beam­lines form the basis of our model which is bench­marked against sim­pli­fied track­ing sim­u­la­tions. Re­al­is­tic beam dis­tri­b­u­tions ob­tained via track­ing around ELENA in the pres­ence of col­lec­tive ef­fects and elec­tron cool­ing will be prop­a­gated along the op­ti­mised 3D trans­fer model to achieve the best beam qual­ity pos­si­ble for the ex­per­i­ments. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF016  
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THPAF020 Measurement of Transverse Impedance of Specific Components in CESR Using BPM Measurements of Pinged Bunches impedance, undulator, cavity, betatron 2990
 
  • M.P. Ehrlichman, J.P. Shanks, S. Wang
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  A beam-based tech­nique is ap­plied to de­ter­mine the quadru­pole im­ped­ance of large-im­ped­ance com­po­nents of the CESR stor­age ring. Two bunches sep­a­rated by ~1/3 of the ring cir­cum­fer­ence are charged to 0.85 and 0.3 mA. Each bunch is given a sin­gle kick, ei­ther hor­i­zon­tal or ver­ti­cal. Turn-by-turn, bunch-by-bunch po­si­tion in­for­ma­tion is recorded for ~16 k turns. BPM-by-BPM phase is cal­cu­lated using the All-phase FFT method of spec­tral analy­sis. The dif­fer­ence in the BPM-to-BPM phase ad­vance be­tween the two bunches is a mea­sure­ment of the local trans­verse im­ped­ance. The im­ped­ances of the small-aper­ture in-vac­uum un­du­la­tors, col­li­ma­tors, scrap­ers, RF cav­i­ties, elec­tro­sta­tic sep­a­ra­tors, and bulk im­ped­ance of the re­main­ing ring are de­ter­mined in this man­ner.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF020  
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THPAF062 Impact of Superconducting Magnet Protection Equipment on the Circulating Beam in HL-LHC dipole, quadrupole, simulation, shielding 3115
 
  • M. Valette, L. Bortot, A.M. Fernandez Navarro, B. Lindstrom, M. Mentink, R. Schmidt, E. Stubberud, A.P. Verweij, D. Wollmann
    CERN, Geneva, Switzerland
  • E. Ravaioli
    LBNL, Berkeley, California, USA
  
  Funding: Work supported by the HL-LHC project.
The new su­per­con­duct­ing quadru­pole and di­pole mag­nets for the High Lu­mi­nos­ity LHC (HL-LHC) will rely on quench heaters or Cou­pling-Loss In­duced Quench (CLIQ) units or a com­bi­na­tion of both to pro­tect the mag­net coils in case of a quench. After the de­tec­tion of a quench, the quench heater power sup­plies will dis­charge cur­rents of sev­eral hun­dreds of am­peres into the quench heater strips glued to the coils, and the CLIQ units will dis­charge an os­cil­lat­ing cur­rent in the order of 1~kA di­rectly into the coils. These cur­rents can have a sig­nif­i­cant ef­fect on the cir­cu­lat­ing beam if the dis­charge oc­curs be­fore the beam is dumped. In the HL-LHC inner triplet quadru­pole mag­nets and 11 T di­pole mag­nets, which will be in­stalled in the col­li­ma­tion re­gion dis­per­sion sup­pres­sor, this ef­fect will even be stronger due to the larger num­ber of quench heaters and use of CLIQ units (triplet mag­nets only) as well as due to the greater value of beta func­tion in com­par­i­son with the pre­sent LHC. In this paper, the ex­pected ef­fects of quench heater and CLIQ dis­charges on the cir­cu­lat­ing beam are sum­ma­rized, and sev­eral mit­i­ga­tion meth­ods are pro­posed and eval­u­ated.
Matthieu. Valette@cern.ch 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF062  
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THPAF068 Suppression of Instabilities Generated by an Anti-Damper With a Nonlinear Magnetic Element in IOTA simulation, lattice, optics, damping 3134
 
  • E.G. Stern, J.F. Amundson, A. Macridin
    Fermilab, Batavia, Illinois, USA
  
  Funding: US Department of Energy
The In­te­grable Op­tics Test Ac­cel­er­a­tor (IOTA) stor­age ring is being con­structed at Fer­mi­lab as a test­bed for new ac­cel­er­a­tor con­cepts. One im­por­tant se­ries of ex­per­i­ments tests the use of a novel non­lin­ear mag­netic in­sert to damp co­her­ent in­sta­bil­i­ties. To test the damp­ing power of the ele- ment, an in­sta­bil­ity of de­sired strength may be in­ten­tion­ally ex­cited with an anti-damper. We re­port on sim­u­la­tions of beam sta­bi­liza­tion using the Syn­er­gia mod­el­ing frame­work over ranges of dri­ving and damp­ing strengths. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF068  
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THPAF073 Beam Phase Space Tomography at Fast Electron Linac at Fermilab lattice, coupling, MMI, linac 3146
 
  • A.L. Romanov
    Fermilab, Batavia, Illinois, USA
  
  FAST lin­ear ac­cel­er­a­tor has been com­mis­sioned in 2017. Ex­per­i­men­tal pro­gram of the fa­cil­ity re­quires high qual­ity beams with well-de­fined prop­er­ties. So­le­noidal fields at pho­toin­jec­tor, laser spot shape, space charge forces and other ef­fects can dis­tort beam dis­tri­b­u­tion and in­tro­duce cou­pling. This work pre­sents re­sults of a beam phase space to­mog­ra­phy for a cou­pled 4D case. Beam was ro­tated in two planes with seven quads by 180 de­grees and im­ages from YaG screen were used to per­form SVD based re­con­struc­tion of the beam dis­tri­b­u­tion.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF073  
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THPAK022 Beam Dynamic Simulation for the Beam Line from Charge Breeder to ALPI for SPES Project rfq, simulation, linac, quadrupole 3255
 
  • M. Comunian, L. Bellan, A. Pisent
    INFN/LNL, Legnaro (PD), Italy
  • A.V. Ziiatdinova
    ITEP, Moscow, Russia
  • A.V. Ziiatdinova
    MEPhI, Moscow, Russia
  
  The SPES pro­ject (Se­lec­tive Pro­duc­tion of Ex­otic Species) is under de­vel­op­ment at INFN-LNL. This fa­cil­ity is in­tended for pro­duc­tion of neu­tron-rich Ra­dioac­tive Ion Beams (RIBs) by ISOL method. The +1 charged beam will be trans­formed to n+ charge by Charge Breeder (Elec­tron Cy­clotron res­o­nance ion source) and reac­cel­er­ated by the ALPI (Ac­cel­er­a­tore Lin­eare Per Ioni) su­per­con­duct­ing Linac . This paper in­cludes re­sults of beam dy­namic sim­u­la­tion at the beam line from Charge Breeder to ALPI.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK022  
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THPAK024 A new method to measure the Beta function in a Paul trap dipole, lattice, emittance, resonance 3262
 
  • L. Martin, S.L. Sheehy
    JAI, Oxford, United Kingdom
  • K. Ito, H. Okamoto
    HU/AdSM, Higashi-Hiroshima, Japan
  • D.J. Kelliher
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  • S. Machida
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  
  The Sim­u­la­tor of Par­ti­cle Orbit Dy­nam­ics (S-POD) is a lin­ear Paul trap at Hi­roshima Uni­ver­sity, Japan, used to study beam physics. S-POD has so far been used to study res­o­nances in high in­ten­sity beams, pre­dom­i­nantly using a sim­ple al­ter­nat­ing gra­di­ent lat­tice con­fig­u­ra­tion. Re­cently a sim­i­lar ap­pa­ra­tus, the In­tense Beam Ex­per­i­ment (IBEX), has been con­structed at the Ruther­ford Ap­ple­ton Lab in the UK. To use ei­ther of these ex­per­i­ments to study beam dy­nam­ics in more com­plex lat­tice con­fig­u­ra­tions in the fu­ture fur­ther di­ag­nos­tic tech­niques must be de­vel­oped for Paul traps. Here we de­scribe a new method to mea­sure the beta func­tion and emit­tance at a given time in a Paul trap.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK024  
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THPAK045 Summary of Beam Operation Capability at FXR LIA operation, cathode, electron, induction 3316
 
  • Y.H. Wu, J. Ellsworth
    LLNL, Livermore, California, USA
  
  Funding: This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52- 07NA27344.
In this paper we sum­ma­rize the cur­rent beam op­er­a­tion ca­pa­bil­ity of FXR lin­ear in­duc-tion ac­cel­er­a­tor (LIA) at LLNL. Ex­peri-men­tal mea­sure­ments for elec­tron beam pa-ram­e­ters at dif­fer­ent beam op­er­a­tions are pre-sented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK045  
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THPAK046 The Ion-Hose Instability in High-Current Multi-Pulse Induction Linacs electron, simulation, induction, vacuum 3320
 
  • C. Ekdahl
    LANL, Los Alamos, New Mexico, USA
  
  The ion-hose in­sta­bil­ity has long been con­sid­ered a dan­ger for long-pulse, high-cur­rent elec­tron lin­ear in­duc­tion ac­cel­er­a­tors (LIAs)*. This in­sta­bil­ity is en­abled by beam-elec­tron ion­iza­tion of resid­ual back­ground gas in the ac­cel­er­a­tor. The space-charge of the high-en­ergy beam ejects low-en­ergy elec­trons from the ion­ized chan­nel, leav­ing a pos­i­tively-charged ion chan­nel that at­tracts the elec­tron beam. The beam can os­cil­late in the po­ten­tial well around the chan­nel po­si­tion. Like­wise, the elec­tron beam at­tracts the ions, which can os­cil­late about the beam po­si­tion. Be­cause of the vast dif­fer­ences in par­ti­cle mass, the os­cil­la­tions are out of phase, and the am­pli­tudes grow un­sta­bly. The num­ber of in­sta­bil­ity e-fold­ings is pro­por­tional to the chan­nel ion den­sity*, which in turn is pro­por­tional to the back­ground pres­sure and pulse length. This scal­ing of the in­sta­bil­ity growth was demon­strated on the long-pulse DARHT-II lin­ear in­duc­tion ac­cel­er­a­tor (LIA) at Los Alamos**. The ion-hose in­sta­bil­ity is also prob­lem­atic for high-cur­rent multi-pulse LIAs, be­cause ion re­com­bi­na­tion times are so very long at typ­i­cal back­ground pres­sures. More­over, be­cause of low ion chan­nel ion den­si­ties, and mas­sive ions, chan­nel ex­pan­sion is too slow to re­duce the in­sta­bil­ity growth by very much. In par­tic­u­lar, the ion chan­nel is ex­pected to per­sist and its den­sity to in­crease dur­ing the 3-mi­crosec­ond du­ra­tion of a four-pulse burst from the 2-kA, 20-MeV Scor­pius LIA now being de­vel­oped. Re­cent sim­u­la­tions with an ex­per­i­men­tally val­i­dated code that was used to pre­dict DARHT-II growth rates have shown that the mag­netic fo­cus­ing field de­signed for Scor­pius will be strong enough to in­hibit ion-hose in­sta­bil­ity if the back­ground pres­sure is kept below a value that is read­ily at­tain­able with the pre­sent de­signs of in­duc­tion cells and other ac­cel­er­a­tor com­po­nents. De­tails and re­sults of these cal­cu­la­tions are the sub­ject of this pre­sen­ta­tion.
*H. L. Buchanan, Phys. Fluids, vol. 30, pp. 221 - 231, 1987
**C. A. Ekdahl, et al., IEEE Trans. Plasma Sci., vol. 34, pp. 460-466, 2006
 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK046  
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THPAK056 Resonance Identification Studies at the CERN PS resonance, space-charge, sextupole, synchrotron 3350
 
  • F. Asvesta
    NTUA, Athens, Greece
  • H. Bartosik, A. Huschauer, Y. Papaphilippou, G. Sterbini
    CERN, Geneva, Switzerland
  
  In view of the LHC In­jec­tors Up­grade (LIU) and the chal­leng­ing high bright­ness tar­get beam pa­ra­me­ters, a broad range of pos­si­ble work­ing points for the Pro­ton Syn­chro­tron (PS) is being in­ves­ti­gated. High order res­o­nances have been iden­ti­fied, both struc­tural res­o­nances dri­ven by space charge due to the lat­tice har­mon­ics of the PS, and res­o­nances ex­cited by mul­ti­po­lar com­po­nents in the ma­chine. This paper pro­vides a sum­mary of the per­formed tune scan stud­ies, cov­er­ing both ex­per­i­men­tal and sim­u­la­tion re­sults. Fur­ther­more, non-lin­ear analy­sis tech­niques have been used to char­ac­ter­ize the res­o­nances and their ef­fect on the beam in pres­ence of space charge.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK056  
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THPAK058 Planned Detection and Amplification of Infared Synchrotron Radiation for Electron-Beam Diagnostics and Manipulations radiation, laser, synchrotron, synchrotron-radiation 3358
 
  • M.B. Andorf, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • P. Piot
    Fermilab, Batavia, Illinois, USA
  
  Am­pli­fi­ca­tion of beam-in­duced ra­di­a­tion (e.g. syn­chro­tron or un­du­la­tor ra­di­a­tion) is a nec­es­sary com­po­nent of op­ti­cal sto­chas­tic cool­ing of hadrons or heavy ions. We dis­cuss a pro­posal to mea­sure and am­plify syn­chro­tron ra­di­a­tion from a bend­ing mag­net of the Ad­vanced Pho­ton Source. The mea­sure­ments will be in the short-wave­length in­frared re­gion (SWIR) and am­pli­fi­ca­tion will be ac­com­plished using a pumped Chromium:Zinc Se­lenide (Cr:ZnSe) crys­tal with max­i­mum gain at λ≅ 2.2~μm.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK058  
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THPAK060 Transverse-to-Longitudinal Photocathode Distribution Imaging laser, quadrupole, electron, cathode 3361
 
  • A. Halavanau, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • W. Gai, G. Ha, J.G. Power, E.E. Wisniewski
    ANL, Argonne, Illinois, USA
  • G. Ha
    PAL, Pohang, Republic of Korea
  • P. Piot
    Fermilab, Batavia, Illinois, USA
  • G. Qiang
    TUB, Beijing, People's Republic of China
  
  In this paper, we pre­sent a tun­able pi­cosec­ond-scale bunch train gen­er­a­tion tech­nique com­bin­ing a mi­crolens array (MLA) trans­verse laser shaper and a trans­verse-to-lon­gi­tu­di­nal emit­tance ex­change (EEX) beam­line. The mod­u­lated beam­let array is formed at the pho­to­cath­ode with the MLA setup. The re­sult­ing pat­terned elec­tron beam is ac­cel­er­ated to 50 MeV and trans­ported to the en­trance of the EEX setup. A quadru­pole chan­nel is used to ad­just the trans­verse spac­ing of the beam­let array up­stream of the EEX, thereby en­abling the gen­er­a­tion of a bunch train with tun­able sep­a­ra­tion down­stream of the EEX beam­line. Ad­di­tion­ally, the MLA is mounted on a ro­ta­tion stage which pro­vides ad­di­tional flex­i­bil­ity to pro­duce high-fre­quency beam den­sity mod­u­la­tion down­stream of the EEX. Ex­per­i­men­tal re­sults ob­tained at the Ar­gonne Wake­field Ac­cel­er­a­tor (AWA) fa­cil­ity are pre­sented and com­pared with nu­mer­i­cal sim­u­la­tions.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK060  
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THPAK062 Bunch Compression of Flat Beams emittance, simulation, cavity, booster 3368
 
  • A. Halavanau, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • D.J. Crawford, D.R. Edstrom, D. Mihalcea, S. Nagaitsev, P. Piot, A.L. Romanov, J. Ruan, V.D. Shiltsev
    Fermilab, Batavia, Illinois, USA
  
  Funding: This work is supported by the DOE contract No.DEAC02-07CH11359 to the Fermi Research Alliance LLC. A.H. is supported by the DOE under contract No. DE-SC0011831 with Northern Illinois University.
Flat beams can be pro­duced via a lin­ear ma­nip­u­la­tion of canon­i­cal an­gu­lar mo­men­tum (CAM) dom­i­nated beams using a set of skew-quadru­pole mag­nets. Re­cently such beams were pro­duced at Fer­mi­lab Ac­cel­er­a­tor Sci­ence and Tech­nol­ogy (FAST) fa­cil­ity. In this paper, we re­port the re­sults of flat beam com­pres­sion study in a mag­netic chi­cane at an en­ergy of E~32 MeV. Ad­di­tion­ally, we in­ves­ti­gate the ef­fect of en­ergy chirp in the round-to-flat beam trans­form. The ex­per­i­men­tal re­sults are com­pared with nu­mer­i­cal sim­u­la­tions. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK062  
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THPAK063 Electron Beam Pattern Rotation as a Method of Tunable Bunch Train Generation lattice, electron, laser, HOM 3372
 
  • A. Halavanau, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • P. Piot
    Fermilab, Batavia, Illinois, USA
  
  Trans­versely mod­u­lated elec­tron beams can be formed in photo in­jec­tors via mi­crolens array (MLA) UV laser shap­ing tech­nique. Micro lenses can be arranged in polyg­o­nal lat­tices, with re­sult­ing trans­verse elec­tron beam mod­u­la­tion mim­ic­k­ing the lenses pat­tern. Con­ven­tion­ally, square MLAs are used for UV laser beam shap­ing, and gen­er­ated elec­tron beam pat­terns form square beam­let ar­rays. The MLA setup can be placed on a ro­ta­tional mount, thereby ro­tat­ing elec­tron beam dis­tri­b­u­tion. In com­bi­na­tion with trans­verse-to-lon­gi­tu­di­nal emit­tance ex­change beam line, it al­lows to vary beam­lets hor­i­zon­tal pro­jec­tion and tune elec­tron bunch train. In this paper, we ex­tend the tech­nique to the case of dif­fer­ent MLA lat­tice arrange­ments and ex­plore the ben­e­fits of its ro­ta­tional sym­me­tries.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK063  
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THPAK074 Beam Manipulation Using Self-Induced Fields in the SwissFEL Injector wakefield, FEL, electron, laser 3401
 
  • S. Bettoni, P. Craievich, R. Ganter, P. Heimgartner, H. Jöhri, F. Marcellini, S. Reiche
    PSI, Villigen PSI, Switzerland
  
  Sev­eral pos­si­bil­i­ties of ma­nip­u­lat­ing the elec­tron beam using sources of wake­field are being ex­plored. Wake­field have been suc­cess­fully used to re­move or en­hance the en­ergy chirp resid­ual from the mag­netic com­pres­sion to con­trol the free elec­tron laser band­width (dechirper), to lin­earize the com­pressed beam (lin­earizer), to gen­er­ate more bunches to pro­duce two color mode, and to per­form ex­per­i­ments of wake­field ac­cel­er­a­tion. At the Swiss­FEL in­jec­tor we plan to in­stall 2 m long sys­tem to ac­com­mo­date sources of wake­field with dif­fer­ent pe­ri­od­ic­i­ties, each of them as­so­ci­ated with one of the dis­cussed beam ma­nip­u­la­tion. In this paper we sum­ma­rize the de­sign and the char­ac­ter­i­za­tion of the sys­tem and the planned ac­tiv­i­ties.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK074  
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THPAK087 Software-Computing System for Numerical Modelling of Beam Dynamics in Accelerators software, controls, interface, simulation 3435
 
  • E. Krushinevskii, E. Sboeva
    Saint Petersburg State University, Saint Petersburg, Russia
  • S.N. Andrianov, A.N. Ivanov, N.V. Kulabukhova
    St. Petersburg State University, St. Petersburg, Russia
  
  The spec­trum of soft­ware pack­ages for the physics of charged par­ti­cles beams is ex­tremely wide. From most pop­u­lar and ef­fec­tive sys­tems can be al­lo­cated such pro­grams as COSY In­fin­ity, MAD X, MARYLIE, TRANS­PORT. Het­ero­ge­neous in­di­vid­ual for­mats of input and out­put data, the lack of a com­mon and user-friendly in­ter­face and the nar­row spe­cial­iza­tion of these pro­grams poses a num­ber of chal­lenges for the mod­ern re­searchers. It sig­nif­i­cantly re­duces the ef­fec­tive­ness and qual­ity of cor­re­spond­ing com­pu­ta­tional ex­per­i­ments. In this ar­ti­cle we pre­sent a uni­ver­sal tool for au­toma­tion and ac­cel­er­a­tion of com­put­ing ex­per­i­ments. The au­thors con­sider a method for de­vel­op­ing the con­cept and pro­to­type of a cor­re­spond­ing soft­ware pack­age that would com­bine the ad­van­tages of ex­ist­ing (non-com­mer­cial) sys­tems. This soft­ware will be able to unify the input and out­put data for­mat for cer­tain pro­grams, vi­su­al­ize the in­for­ma­tion in var­i­ous ways, pro­vide ref­er­ence and train­ing in­for­ma­tion for "be­gin­ners". The re­sults ob­tained within the de­vel­oped frame­work will be a sig­nif­i­cant con­tri­bu­tion both to the de­vel­op­ment of nu­mer­i­cal and sym­bol­i­cal meth­ods for solv­ing evo­lu­tion non­lin­ear equa­tions.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK087  
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THPAK116 Modeling Surface Roughness Effects and Emission Properties of Bulk and Layered Metallic Photocathode simulation, electron, emittance, cathode 3515
 
  • D.A. Dimitrov, G.I. Bell
    Tech-X, Boulder, Colorado, USA
  • I. Ben-Zvi, J. Smedley
    BNL, Upton, Long Island, New York, USA
  • J. Feng, S.S. Karkare, H.A. Padmore
    LBNL, Berkeley, California, USA
  
  Funding: This work was supported by the Office of Science, Office of Basic Energy Sciences of the U.S. Department of Energy under Contract Nos. DE-SC0013190, DE-AC02-05CH11231, and KC0407-ALSJNT-I0013.
The ther­mal limit of the in­trin­sic emit­tance of pho­to­cath­odes rep­re­sents an im­por­tant prop­erty to mea­sure ex­per­i­men­tally and to un­der­stand the­o­ret­i­cally. De­tailed mea­sure­ments of in­trin­sic emit­tance have be­come pos­si­ble in mo­men­ta­tron ex­per­i­ments. More­over, re­cent de­vel­op­ments in ma­te­r­ial de­sign have al­lowed grow­ing pho­toe­mis­sive lay­ers with con­trolled sur­face rough­ness. Al­though an­a­lyt­i­cal for­mu­la­tions of the ef­fects of rough­ness have been de­vel­oped, a full the­o­ret­i­cal model and ex­per­i­men­tal ver­i­fi­ca­tion are lack­ing. We aim to bridge this gap by de­vel­op­ing re­al­is­tic mod­els for dif­fer­ent ma­te­ri­als in the three-di­men­sional VSim par­ti­cle-in-cell code. We have re­cently im­ple­mented mod­el­ing of elec­tron photo-ex­ci­ta­tion, trans­port, and emis­sion from pho­toe­mis­sive lay­ers grown on a sub­strate. We re­port re­sults from sim­u­la­tions with these mod­els on elec­tron emis­sion from an­ti­mony and gold. We con­sider ef­fects due to den­sity of states, pho­toe­mis­sive layer thick­ness, sur­face rough­ness and how they af­fect the spec­tral re­sponse of quan­tum yield and in­trin­sic emit­tance. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK116  
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THPAK121 Accelerator Optimization through LIV. DAT plasma, proton, radiation, wakefield 3526
 
  • C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: LIV. DAT is supported by the STFC under contract ST/P006752/1.
The Liv­er­pool Big Data Sci­ence (LIV. DAT) Cen­ter for Doc­toral Train­ing (CDT) is a hub for train­ing stu­dents in man­ag­ing, analysing and in­ter­pret­ing large, com­plex datasets and high rates of data flow. LIV. DAT of­fers a unique train­ing ap­proach ad­dress­ing some of the biggest chal­lenges in data in­ten­sive sci­ence to tackle a grow­ing skills gap. It cur­rently pro­vides train­ing to a co­hort of al­most 20 PhD stu­dents. Their re­search pro­jects ad­dress R&D chal­lenges in as­tron­omy, nu­clear, par­ti­cle and ac­cel­er­a­tor physics. This con­tri­bu­tions pre­sents ini­tial re­search re­sults from mod­el­ing stud­ies of the physics and bi­ol­ogy of pro­ton beam ther­apy using a Monte Carlo ap­proach, as well as plasma-beam in­ter­ac­tion in the cases of AWAKE and Eu­PRAXIA. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK121  
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THPAK131 Investigation of Two-Bunch Train Compression by Velocity Bunching bunching, electron, cavity, emittance 3548
 
  • D. Wang, Y. C. Du, W.-H. Huang, X. Liu, X.L. Su, C.-X. Tang, Q.L. Tian, L.X. Yan
    TUB, Beijing, People's Republic of China
  • H. Zhang
    Tsinghua University, Beijing, People's Republic of China
  
  Two elec­tron beam­lets, also re­ferred as two-bunch train with ad­justable time and en­ergy spac­ing are pop­u­lar in many ap­pli­ca­tions such as two color FEL and pump-probe ex­per­i­ments. We in­ves­ti­gate com­pres­sion of two-bunch train via ve­loc­ity bunch­ing scheme in a trav­el­ing wave ac­cel­er­a­tor (TWA) tube by vary­ing the phase of TWA tube in a very large range. Beam dy­nam­ics sim­u­la­tions show that when the phase in­jected into the ac­cel­er­a­tor tube for the beam is set to ≪-100 de­gree, ve­loc­ity bunch­ing oc­curs in a deep over-com­pres­sion mode, where two-bunch train is con­tin­u­ously tun­able in time and in en­ergy space, and the emit­tance of each sub-bunch is also pre­served. In the ex­per­i­ment, we use en­ergy spec­trum and de­fect­ing cav­ity to di­ag­nose the train's en­ergy space and time space re­spec­tively, the mea­sure­ments demon­strated that two-bunch train through deep over-com­pres­sion scheme is sep­a­rated both in time and in en­ergy space, which also agree well with the pre­dic­tions.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK131  
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THPAK137 Beam-Based Sextupolar Nonlinearity Mapping in CESR sextupole, simulation, resonance, lattice 3565
 
  • L. Gupta, Y.K. Kim
    University of Chicago, Chicago, Illinois, USA
  • S. Baturin
    Enrico Fermi Institute, University of Chicago, Chicago, Illinois, USA
  • M.P. Ehrlichman, J.M. Maxson, R.E. Meller, D. L. Rubin, D. Sagan, J.P. Shanks
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: Work supported by the U.S. National Science Foundation under Award No. PHY-1549132, the Center for Bright Beams
In order to main­tain beam qual­ity dur­ing trans­port through a stor­age ring, sex­tu­pole mag­nets are used to make chro­matic cor­rec­tions, but nec­es­sar­ily in­tro­duce dele­te­ri­ous ef­fects such as non­lin­ear res­o­nances and re­duced dy­namic aper­ture. Im­ple­ment­ing in­tri­cate sex­tu­pole dis­tri­b­u­tions to mit­i­gate these ef­fects will rely on pre­ci­sion beam-based mea­sure­ment of the ap­plied sex­tu­pole dis­tri­b­u­tion. In this work, we gen­er­al­ize pre­vi­ous sex­tu­pole map­ping tech­niques by using res­o­nant phase-locked ex­ci­ta­tion of the beam at the Cor­nell Elec­tron Stor­age Ring (CESR), which ac­counts for vari­a­tions in the nor­mal mode tunes on a turn by turn basis. The meth­ods pre­sented here are ap­plied to sim­u­la­tion and ac­tual turn by turn data in CESR for both sim­pli­fied and re­al­is­tic sex­tu­pole dis­tri­b­u­tions. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK137  
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THPAK139 Lost Muon Studies for the Muon g-2 Experiment at Fermilab positron, storage-ring, background, resonance 3573
 
  • S. Ganguly, K. T. Pitts
    University of Illinois at Urbana-Champaign, Urbana, USA
  • J.D. Crnkovic
    BNL, Upton, Long Island, New York, USA
  • C. C. Polly
    Fermilab, Batavia, Illinois, USA
  
  The Fer­mi­lab Muon g-2 ex­per­i­ment aims to mea­sure the muon anom­alous mag­netic mo­ment aμ with an un­prece­dented pre­ci­sion of 140 parts per bil­lion (ppb), a four-fold im­prove­ment over the 540~ppb pre­ci­sion ob­tained by the BNL Muon g-2 Ex­per­i­ment. This study pre­sents pre­lim­i­nary work on es­ti­mat­ing the muon losses by using dou­ble co­in­ci­dences in the calorime­ters.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK139  
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THPAK141 Initial Tests of Nonlinear Quasi-Integrable Optics at the University of Maryland Electron Ring octupole, electron, optics, simulation 3581
 
  • H. Baumgartner, B.L. Beaudoin, I. Haber, T.W. Koeth, D.B. Matthew, K.J. Ruisard
    UMD, College Park, Maryland, USA
  
  Funding: Funding for this project and travel is provided by DOE-HEP, NSF GRFP and NSF Accelerator Science Program.
An oc­tu­pole chan­nel has been in­serted into the Uni­ver­sity of Mary­land Elec­tron Ring (UMER), in order to in­ves­ti­gate the mit­i­ga­tion of de­struc­tive res­o­nances as a novel ap­proach in high-in­ten­sity beam trans­port. The in­di­vid­ual oc­tu­pole mag­nets have been char­ac­ter­ized using our in-house 3-di­men­sional mag­net map­ping stage, with a mea­sured gra­di­ent of 51.6 ± 1.5 T/m3/A. A sin­gle sec­tion (20°) of an 18-cell FODO lat­tice has been re­placed by a lon­gi­tu­di­nally-vary­ing oc­tu­pole chan­nel con­structed from seven flex­i­ble printed cir­cuits (PCBs). We pre­sent the de­sign of the chan­nel and pre­lim­i­nary beam based mea­sure­ments on the ring. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK141  
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THPAK143 Tuning Low-Current Beam for Nonlinear Quasi-Integrable Optics Experiments at the University of Maryland Electron Ring lattice, octupole, optics, quadrupole 3585
 
  • K.J. Ruisard, H. Baumgartner, B.L. Beaudoin, S. Bernal, B. M. Cannon, L. Dovlatyan, I. Haber, T.W. Koeth
    UMD, College Park, Maryland, USA
  
  Funding: Travel was supported by the NSF, the APS DPB, and TRIUMF. Funding for the work was provided through DOE-HEP Award DESC0010301, NSF Award PHY1414681 and the NSF GRFP program.
De­sign of ac­cel­er­a­tor lat­tices with non­lin­ear in­te­grable op­tics is a novel ap­proach to sup­press trans­verse res­o­nances and may be cru­cial for en­abling low-loss high-in­ten­sity beam trans­port. Lat­tices with large am­pli­tude-de­pen­dent tune spreads, dri­ven by strong non­lin­ear mag­net in­serts, have re­duced re­sponse to res­o­nant dri­ving per­tur­ba­tions [*]. This paper de­scribes prepa­ra­tions for tests of a quasi-in­te­grable oc­tu­pole lat­tice at the Uni­ver­sity of Mary­land Elec­tron Ring (UMER). The planned tests em­ploy a low-cur­rent high­emit­tance beam with low space charge tune shift (∼ 0.005) to probe the dy­nam­ics of a lat­tice with large ex­ter­nal tune spread (∼ 0.26).
* V. Danilov and S. Nagaitsev, Nonlinear accelerator lattices
with one and two analytic invariants, PRSTAB, 13, 084002, 2010. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK143  
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THPAL010 Sector DC Dipoles Design for the Beam Test Facility Upgrade dipole, linac, quadrupole, electron 3634
 
  • A. Vannozzi, S. Lauciani, L. Pellegrino, L. Sabbatini, C. Sanelli, G. Sensolini
    INFN/LNF, Frascati (Roma), Italy
  • P. Valente
    INFN-Roma, Roma, Italy
  
  The Beam Test Fa­cil­ity is part of the DAΦNE ac­cel­er­a­tors sys­tem of INFN Fras­cati Na­tional Lab­o­ra­tory. It is a trans­fer-line op­ti­mized for elec­trons and positrons ex­tracted from the DAΦNE LINAC. An up­grade of the line is sched­uled for two pur­poses: reach a beam en­ergy of 920 MeV (with re­spect to the ac­tual 750 MeV) and add a new branch to the pre­sent trans­fer line. This new lay­out fore­sees six new quadrupoles one fast ramped di­pole, two H-shape and one C-shape sec­tor dipoles. The de­sign of the mag­nets has been com­pletely per­formed at INFN in­volv­ing Electro­mechan­i­cal En­ter­prise part­ner in the de­sign phase in order to op­ti­mise the man­u­fac­tur­ing process. This ef­fort lead to a com­plete set of de­tailed CAD draw­ings that can be di­rectly used by man­u­fac­turer to build the mag­nets. The goal is to boost the man­u­fac­tur­ing of pro­to­types and small se­ries from Small and Medium En­ter­prises. Mag­netic mea­sure­ments will be per­formed at INFN. This poster is fo­cused on the re­al­iza­tion of the two full iron yoke H-shape and C-shape dipoles, re­spec­tively with 45 and 15 bend­ing angle. They are char­ac­ter­ized by a high flux den­sity of 1.7 T in a gap of 35 mm. They have a bend­ing ra­dius of 1.8 m  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL010  
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THPAL029 Comparison of Horizontal and Vertical Electropolishing Methods using Niobium Single-Cell Coupon Cavity cavity, cathode, niobium, accumulation 3692
 
  • V. Chouhan, Y.I. Ida, K.N. Nii, T.Y. Yamaguchi
    MGH, Hyogo-ken, Japan
  • H. Hayano, S. Kato, H. Monjushiro, T. Saeki, M. Sawabe
    KEK, Ibaraki, Japan
  
  Hor­i­zon­tal elec­trop­o­l­ish­ing (HEP) is an es­tab­lished tech-nique for sur­face treat­ment of nio­bium ac­cel­er­at­ing cavi-ties. Ver­ti­cal elec­trop­o­l­ish­ing (VEP), in which the cav­ity is elec­trop­o­l­ished in the ver­ti­cal pos­ture, is in R&D phase for pa­ra­me­ter op­ti­miza­tion. We per­formed HEP and VEP of a nio­bium sin­gle-cell coupon cav­ity to com­pare the ef­fect of both the meth­ods on sur­face state and re­moval at dif­fer­ent po­si­tions of the cav­ity. HEP was per­formed at STF, KEK with the stan­dard EP pa­ra­me­ters. VEP was per­formed at Marui Gal­va­niz­ing Com­pany with a cath­ode called 'Ninja cath­ode' that can be ro­tated dur­ing the VEP process. The op­ti­mized cath­ode de­sign and VEP parame-ters re­sulted in sym­met­ric re­moval as ob­tained with the HEP tech­nique and yielded a smooth inner sur­face of the en­tire cav­ity  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL029  
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THPAL032 1.3GHz Nb Single-Cell Cavity Vertical Electropolishing with Ninja Cathode and Results of Vertical Test cavity, cathode, accelerating-gradient, factory 3702
 
  • K.N. Nii, V. Chouhan, Y.I. Ida, T.Y. Yamaguchi
    MGH, Hyogo-ken, Japan
  • H. Hayano, S. Kato, H. Monjushiro, T. Saeki, M. Sawabe
    KEK, Ibaraki, Japan
  • H. Ito
    Sokendai, Ibaraki, Japan
  • H. Oikawa
    Utsunomiya University, Utsunomiya, Japan
  
  Marui Gal­va­niz­ing Co., Ltd. has been de­vel­op­ing Nb cav­ity ver­ti­cal elec­trop­o­l­ish­ing (VEP) tech­nolo­gies in col­lab­o­ra­tion with KEK. Until now, we re­ported that inner sur­face state and re­moval thick­ness dis­tri­b­u­tion were im­proved in VEP with Ninja cath­ode and coupon cav­ity. This time, a 1.3GHz Nb sin­gle-cell cav­ity VEP with Ninja cath­ode was per­formed in Marui and ver­ti­cal test was per­formed in KEK. The inner sur­face state and re­moval thick­ness dis­tri­b­u­tion were sat­is­fac­tory. And as a re­sult of ver­ti­cal test, the ac­cel­er­at­ing gra­di­ent of 32MV/m (Q0=8.0E9) was achieved.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL032  
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THPAL033 Measurement of the Internal Dark Current in a High Gradient Accelerator Structure at 17 GHz multipactoring, acceleration, electron, simulation 3705
 
  • H. Xu, M.A. Shapiro, R.J. Temkin
    MIT/PSFC, Cambridge, Massachusetts, USA
  
  Funding: Work supported by the U.S. Department of Energy, Office of High Energy Physics, under Grant No. DE-SC0015566
We re­port a study of in­ter­nal dark cur­rent gen­er­a­tion by mul­ti­pactor in­side a 17 GHz sin­gle cell stand­ing wave disk-loaded wave­guide ac­cel­er­a­tor struc­ture. The mul­ti­pactor takes place on the side wall of the cen­tral cell, dri­ven by the local rf elec­tric and mag­netic fields. The­ory in­di­cates that a res­o­nant mul­ti­pactor mode with two rf cy­cles can be ex­cited near 45 MV/m gra­di­ent and a sin­gle rf cycle mul­ti­pactor mode near 60 MV/m. The ac­cel­er­a­tor struc­ture had two thin slits opened on the side wall of the cen­tral cell to di­rectly ex­tract and mea­sure the in­ter­nal dark cur­rent. The dark cur­rent was mea­sured as a func­tion of the gra­di­ent up to a gra­di­ent of 70 MV/m. The ex­per­i­men­tal re­sults agreed well with the­ory, show­ing the two pre­dicted mul­ti­pactor modes. To fur­ther study the ef­fect of the cen­tral cell side wall sur­face prop­er­ties on the struc­ture per­for­mance, we pre­pared and tested a sec­ond struc­ture with the cen­tral cell side wall coated with a layer of di­a­mond-like car­bon. The com­par­i­son of the re­sults showed that the coat­ing re­duced the in­ter­nal dark cur­rent and thus en­hanced the struc­ture per­for­mance con­sid­er­ably. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL033  
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THPAL039 Improved Magnetron Stability and Reduced Noise in Efficient Transmitters for Superconducting Accelerators controls, SRF, cavity, feedback 3726
 
  • G.M. Kazakevich, R.P. Johnson
    Muons, Inc, Illinois, USA
  • V.A. Lebedev, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  State of the art high-cur­rent su­per­con­duct­ing ac­cel­er­a­tors re­quire ef­fi­cient RF sources with a fast dy­namic phase and power con­trol. This al­lows for com­pen­sa­tion of the phase and am­pli­tude de­vi­a­tions of the ac­cel­er­at­ing volt-age in the Su­per­con­duct­ing RF (SRF) cav­i­ties caused by mi­cro­phon­ics, etc. Ef­fi­cient mag­netron trans­mit­ters with fast phase and power con­trol are at­trac­tive RF sources for this ap­pli­ca­tion. They are more cost ef­fec­tive than tra­di­tional RF sources such as kly­strons, IOTs and solid-state am­pli­fiers used with large scale ac­cel­er­a­tor pro­jects. How­ever, un­like tra­di­tional RF sources, con­trolled mag­netrons op­er­ate as forced os­cil­la­tors. Study of the im­pact of the con­trol­ling sig­nal on mag­netron sta­bil­ity, noise and ef­fi­ciency is there­fore im­por­tant. This paper dis­cusses ex­per­i­ments with 2.45 GHz, 1 kW tubes and ver­i­fies our an­a­lyt­i­cal model which is based on the charge drift ap­prox­i­ma­tion.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL039  
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THPAL040 Lossy Beam Pipe HOM Load Ceramics with DC Conductivity vacuum, HOM, site, controls 3729
 
  • M.L. Neubauer, A. Dudas
    Muons, Inc, Illinois, USA
  • F. Marhauser
    JLab, Newport News, Virginia, USA
  
  The ce­ramic ma­te­ri­als used in the beam pipe for su­per-con­duct­ing RF ac­cel­er­a­tors have the prob­lem of charg­ing due to the elec­tron cloud and sec­ondary elec­tron emis­sion. A novel so­lu­tion is in the ap­pli­ca­tion of con­duc­tive nanopar­ti­cles to the lossy ce­ramic. The lossy ce­ramic is pre-processed to pro­vide for pores that will ac­cept the con­duc­tive nanopar­ti­cles and then coated with a thin film to pre­vent the nanopar­ti­cles from en­ter­ing the en­vi­ron­ment. The same process was also done with sub-mi­cron car­bon par­ti­cles. Mea­sure­ments of sur­face con­duc­tiv­ity with and with­out a vac­uum com­pat­i­ble sealant are re­ported on along with mi­crowave mea­sure­ments.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL040  
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THPAL044 The Permanent Magnets Magnetic Characteristics Change Under Effect of 10 MeV Beam radiation, electron, permanent-magnet, ECR 3742
 
  • I.S. Guk, O.M. Bovda, V.O. Bovda, A.N. Dovbnya, A.I. Kalinichenko, S.S. Kandybey, V.N. Ljashchenko, A. Mytsykov, L.V. Onishchenko, O.A. Repikhov, A.Y. Zelinsky
    NSC/KIPT, Kharkov, Ukraine
  
  Mag­nets of ap­plied elec­tron ac­cel­er­a­tors are under di­rect ef­fect of elec­trons and bremsstrahlung ra­di­a­tion stip­u­lated by the elec­tron beam. The choice of the ma­te­ri­als for the rare el­e­ments alloy ac­cel­er­a­tor mag­nets has the de­ci­sive im­por­tance for the long term mag­net pa­ra­me­ters keep­ing. The ex­per­i­men­tal stud­ies of the mag­netic fields around the Nd-Fe-B and Sm2­Co17 alloy mag­nets under ef­fect of the elec­tron beam have been done. The sam­ples of 30х24х12 mm geo­met­ri­cal sizes were bom­barded by elec­tron beam of ap­plied NSC KIPT ac­cel­er­a­tor KUT-1 with elec­tron en­ergy of 10 MeV and were ir­ra­di­ated by cor­re­spon­dent bremsstrahlung. The mag­netic field value around Nd-Fe-B alloy sam­ples was de­creased non­lin­eary under elec­tron beam bom­bard­ing with change of ir­ra­di­a­tion doze from 16 to 160 GRad. Under ef­fect of bremsstrahlung the mag­netic field value around sam­ples was not changed. The re­peated sam­ple mag­ne­ti­za­tions al­lowed to re­store the ini­tial mag­netic field dis­tri­b­u­tion around mag­nets. The mag­netic field dis­tri­b­u­tion around Sm2­Co17 alloy sam­ples was not changed under ef­fect of the elec­tron beam and bremsstrahlung within ir­ra­di­a­tion dozes men­tioned above. The in­duced ac­tiv­ity in the Nd-Fe-B and Sm2­Co17 alloy sam­ples was changed slightly dur­ing the ex­per­i­ments.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL044  
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THPAL057 Development of the Aluminum Beam Duct for the Ultra-Low Emittance Light Source vacuum, storage-ring, impedance, emittance 3775
 
  • G.-Y. Hsiung, J.-R. Chen, C.M. Cheng, S-N. Hsu, H.P. Hsueh, Y.C. Yang
    NSRRC, Hsinchu, Taiwan
  • J.-R. Chen
    National Tsing Hua University, Hsinchu, Taiwan
  
  The fu­ture light source with ul­tra-low emit­tance, typ­i­cally < 500 pm rad, re­quests the beam duct with inner aper­ture < 20 mm for the elec­tron stor­age ring. Be­sides, the cross sec­tion of the beam duct must be kept smooth for low­er­ing the im­ped­ance. The alu­minum ex­truded beam duct of 10 mm in­side and 1 ~ 2 m in length was de­vel­oped for this pur­pose. The beam duct was ma­chined in ethanol to ob­tain a clean sur­face for a lower ther­mal out­gassing rate. To mit­i­gate the im­ped­ance of the flange con­nec­tion, a spe­cial de­signed di­a­mond-edge gas­ket and the alu­minum flange with­out knife edge were de­vel­oped. The inner di­am­e­ters of both flange and gas­ket, 10 mm, are the same as that of beam duct. The seal­ing of the gas­ket has been proved leak-tight. The ul­ti­mate pres­sure and the ther­mal out­gassing rate of the beam duct has achieved < 2.0·10-10 Torr and < 1.4·10-13 Torr l/(s cm2), re­spec­tively after bak­ing. Those re­sults ful­fill both the ul­tra­high vac­uum and low­est im­ped­ance are ap­plic­a­ble for the next gen­er­a­tion ul­tra-low emit­tance light source.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL057  
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THPAL058 Effect of Ozonated Water Cleaning on Photon Stimulated Desorption in a Stainless Steel Chamber photon, vacuum, ECR, radiation 3778
 
  • C.M. Cheng, C.K. Chan, C.-C. Chang, Y.T. Cheng, J. -Y. Chuang, G.-Y. Hsiung, L.H. Wu, Y.C. Yang
    NSRRC, Hsinchu, Taiwan
  
  Alu­minium vac­uum cham­bers cleaned with ozonated water show a re­duc­tion of resid­ual car­bon and lower sur­face out­gassing rate after bak­ing. We would like to in­ves­ti­gate if stain­less steel cham­bers show sim­i­lar ef-fects. A stain­less steel test cham­ber was cleaned by stand-ard chem­i­cal clean­ing only and then com­pared with an-other one after im­mer­sion in 30ppm ozonated water for thirty min­utes. Both sam­ples were baked, then pho­ton ex­posed and the pho­ton des­orp­tion yields were de­ter-mined by vac­uum gauges and resid­ual gas analy­sers at the TLS 19B beam­line. The test re­sults on pho­ton stim­u­lated des­orp­tion yields and par­tial pres­sure vari­a­tions with and with­out ozonated water clean­ing of the stain­less steel tubes will be dis­cussed in some de­tail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL058  
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THPAL060 Advanced Modeling of Klystrons by the Tesla-Family of Large-Signal Codes klystron, cavity, impedance, simulation 3785
 
  • I.A. Chernyavskiy, D.K. Abe, B. Levush, A.N. Vlasov
    NRL, Washington, DC, USA
  • T.M. Antonsen
    UMD, College Park, Maryland, USA
  • T.M. Antonsen
    Leidos Corp, Billerica, MA, USA
  • J. Rodgers
    Naval Research Laboratory (NRL), Washington, USA
  
  Funding: US Office of the Naval Research
Kly­strons and IOTs are widely used or pro­posed to be used in ac­cel­er­a­tors as high-power RF sources. De­vel­op­ment and op­ti­miza­tion of kly­stron and IOT de­signs is aided by the use of dif­fer­ent sim­u­la­tion tools, in­clud­ing highly ef­fi­cient large-sig­nal codes. We pre­sent an overview of the ad­vances in the code de­vel­op­ment and mod­el­ing using Naval Re­search Lab­o­ra­tory (NRL) set of TESLA-fam­ily of large-sig­nal codes, suit­able for the mod­el­ing of sin­gle-beam and mul­ti­ple beam kly­strons and IOTs. Orig­i­nal 2D large-sig­nal al­go­rithm of the code TESLA* was de­vel­oped for the mod­el­ing of kly­strons based on (rel­a­tively) high Q res­onators and is ap­plic­a­ble to the mul­ti­ple-beam de­vices in an ap­prox­i­ma­tion of iden­ti­cal beams/beam-tun­nels. Par­al­lel ex­ten­sion of TESLA al­go­rithm (code TESLA-MB**) en­abled an ac­cu­rate, quasi-3D mod­el­ing of mul­ti­ple-beam de­vices with non-iden­ti­cal beams/beam-tun­nels. Re­cently de­vel­oped more gen­eral TESLA-Z al­go­rithm*** is based on the im­ped­ance ma­trix ap­proach and en­abled geom­e­try-dri­ven large-sig­nal mod­el­ing. Ex­am­ples of ap­pli­ca­tions of TESLA-fam­ily of codes to the mod­el­ing of ad­vanced sin­gle-beam and mul­ti­ple-beam kly­strons (and IOTs) will be pre­sented.
*A.N. Vlasov, et al,IEEE TPS, v.30(3), 1277-1291, June 2002
**I.A. Chernyavskiy, et al.,IEEE TPS, v.36(3), 670-681, June 2008
***I.A. Chernyavskiy, et al.,IEEE TED, v.64(2), 536-542, Feb 2017 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL060  
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THPAL064 Burst-Mode UV Enhancement Cavity for Laser-Assisted Hydrogen Ion Beam Stripping at SNS cavity, laser, resonance, controls 3799
 
  • A. Rakhman, Y. Liu
    ORNL, Oak Ridge, Tennessee, USA
  
  Funding: This work has been supported in part by U.S. DOE grant DE-FG02-13ER41967. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE.
Re­cent suc­cess of laser-as­sisted charge ex­change for 10 μs du­ra­tion Hy­dro­gen ion beams at SNS mo­ti­vates laser de­vel­op­ment nec­es­sary for ef­fi­cient strip­ping of 1.0 ms du­ra­tion beam at full duty cycle. To over­come the laser power chal­lenge, the in­ter­ac­tion point was cho­sen in­side an op­ti­cal cav­ity. A dou­bly-res­o­nant en­hance­ment cav­ity and a novel lock­ing tech­nique have been de­vel­oped, and a co­her­ent en­hance­ment of 402.5 MHz, 50 ps, 1.05 MW peak power ul­tra­vi­o­let (355 nm) laser pulses op­er­at­ing at 10-μs/10-Hz burst mode has been demon­strated. This will en­able 1.0 ms du­ra­tion laser macropulses at 60 Hz to be stored in­side such a cav­ity to achieve ef­fi­cient strip­ping at SNS. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL064  
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THPAL069 Simulation of a 10 mm Diameter Cascaded Plasma Window plasma, cathode, simulation, vacuum 3812
 
  • P.P. Gan, S. Huang, Y.R. Lu, S.Z. Wang, K. Zhu
    PKU, Beijing, People's Republic of China
  
  As a win­dow­less vac­uum de­vice, the 10 mm di­am­e­ter 60 mm long plasma win­dow de­signed by Peking Uni­ver­sity only achieved to sep­a­rate 28.8 kPa from 360 Pa ex­per­i­men­tally with 50 A di­rect cur­rent and 2.5 kW power. Based on our 10 mm di­am­e­ter plasma win­dow, we have pro­posed a cas­caded plasma win­dow to achieve the iso­la­tion of at­mos­phere and high vac­uum. In this paper, a nu­mer­i­cal 2D FLU­ENT-based mag­neto-hy­dro­dy­namic sim­u­la­tion on 10 mm di­am­e­ter cas­caded plasma win­dow was de­vel­oped. The gas inlet, arc cre­ation and plasma ex­pan­sion seg­ments are all con­tained in this model. A set of pa­ra­me­ters in­clud­ing pres­sure, tem­per­a­ture, ve­loc­ity and cur­rent dis­tri­b­u­tion were ob­tained and analysed. In our first sim­u­la­tion, the iso­la­tion of 100 kPa and 50 Pa pres­sure has been re­alised, and some in­ter­est­ing phe­nom­ena oc­curred.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL069  
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THPAL071 Preliminary Emittance Measurement of Laser Driven Proton Beam Employing a Quadruple Triplet Magnet proton, emittance, laser, quadrupole 3818
 
  • Wu,M.J. Wu, Y.X. Geng, Q. Liao, C. Lin, H.Y. Lu, Y.R. Lu, W.J. Ma, Y.R. Shou, X. Xu, X.Q. Yan, Y.Y. Zhao, J.G. Zhu, K. Zhu
    PKU, Beijing, People's Republic of China
  
  The Com­pact Laser Plasma Ac­cel­er­a­tor (CLAPA) has been built re­cently at Peking Uni­ver­sity, which com­posed of a 200TW laser ac­cel­er­a­tion plat­form and a beam line sys­tem. Pro­ton with en­ergy spread of <1%, up to 10 pC charge and dif­fer­ent en­er­gies below 10 MeV have been pro­duced and trans­ported to the ir­ra­di­a­tion plat­form. Emit­tance is a crit­i­cal pa­ra­me­ter for beam trans­porta­tion. The pre­lim­i­nary emit­tance mea­sure­ment has been per-formed for CLAPA's pro­ton beams using the quadru­pole scan tech­nique (QST). In the ex­per­i­ment, the focal spot size of the pro­ton beam was changed by scan­ning the cur­rent of a quadru­pole triplet mag­net. The re­sult shows that the nor­mal­ized emit­tance is smaller than 0.01 mm·mrad for 5 MeV laser dri­ven pro­tons, which is on the same level of the pre­vi­ously re­ported work.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL071  
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THPAL074 Numerical Studies of Normal Conducting Deflecting Cavity Designs for the ELBE Accelerator cavity, HOM, electron, impedance 3824
 
  • T.G. Hallilingaiah, U. van Rienen
    Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
  • A. Arnold, U. Lehnert, P. Michel
    HZDR, Dresden, Germany
  
  Cur­rently, in the elec­tron linac ELBE there is a sin­gle beam line. There­fore, at any given time only sin­gle user can use the beam. More­over, as dif­fer­ent user ex­per­i­ments re­quire dis­tinct beam in­ten­sity set­tings, not all the ex­per­i­ments fully uti­lize the 13 MHz CW beam ca­pa­bil­ity of the fa­cil­ity. To uti­lize the full beam ca­pac­ity, mul­ti­ple beam lines can be es­tab­lished by using an array of trans­verse de­flect­ing struc­tures. For that, an RF cav­ity was the de­sign choice due to its in­her­ent ad­van­tages with re­spect to re­peata­bil­ity of the kick volt­age am­pli­tude and phase, and the pos­si­bil­ity of CW op­er­a­tion in the MHz range. Po­ten­tial de­sign can­di­dates are the CEBAF RF sep­a­ra­tor, the three pro­posed crab cav­i­ties for the HL-LHC up­grade pro­ject, and a novel NC de­flect­ing cav­ity de­sign. In this com­par­a­tive study, the fig­ures of merit of the cav­i­ties are com­puted from elec­tro­mag­netic field sim­u­la­tions for a trans­verse volt­age of 300 kV. This com­par­a­tive study sup­ported our se­lec­tion of the de­flect­ing cav­ity de­sign for ELBE.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL074  
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THPAL076 Experimental Methods for the Assessment of NEG Pumps Working in Dust-Sensitive Environments vacuum, cavity, SRF, background 3828
 
  • T. Porcelli, E. Maccallini, P. Manini, M. Mura, M.F. Urbano
    SAES Getters S.p.A., Lainate, Italy
  
  NEG pumps have been widely adopted by many ac­cel­er­a­tor fa­cil­i­ties since decades. How­ever, their use in dust-sen­si­tive areas - such as su­per­con­duc­tive radio fre­quency (SRF) cav­i­ties - has al­ways been lim­ited by con­cerns about ac­ci­den­tal dust emis­sion, which could in­duce detri­men­tal field emis­sion. As fu­ture ma­chines will nec­es­sar­ily rely on highly-ef­fi­cient SRF cav­i­ties, able to sup­ply very high ac­cel­er­at­ing gra­di­ents, re­quire­ments in terms of par­ti­cle re­lease from vac­uum com­po­nents (e.g., pumps and valves) are be­com­ing more and more strin­gent. At the same time, achiev­ing sta­ble ul­tra-high vac­uum con­di­tions is cru­cial, as con­densed resid­ual gas might also be a po­ten­tial source of field emis­sion. At pre­sent, a uni­fied stan­dard pro­ce­dure to as­sess dust gen­er­a­tion and prop­a­ga­tion along a ma­chine is still miss­ing and dis­cus­sions are on­go­ing in the vac­uum com­mu­nity. Re­cent ex­per­i­men­tal mea­sure­ments demon­strated the com­pat­i­bil­ity of sin­tered NEG pumps with ul­tra-clean en­vi­ron­ments, due to their in­trin­sic very low dust re­lease. In par­al­lel, in-situ tests per­formed at dif­fer­ent ac­cel­er­a­tor fa­cil­i­ties showed ab­sence of dust con­t­a­m­i­na­tion from NEGs and no im­pact on cav­i­ties ef­fi­ciency.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL076  
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THPAL089 Design, Assembly and Commissioning of a New Cryogenic Facility for Complex Superconducting Thin Film Testing SRF, site, cavity, operation 3859
 
  • O.B. Malyshev, L. Bizel-Bizellot, K.D. Dumbell, P. Goudket, N. Pattalwar, S.M. Pattalwar, P. Pizzol, P.A. Smith, R. Valizadeh, S. Wilde
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • P. Pizzol
    The University of Liverpool, Liverpool, United Kingdom
  
  An on­go­ing study on the su­per­con­duct­ing thin films for fu­ture su­per­con­duct­ing RF cav­i­ties re­quires an in­tense test­ing of var­i­ous su­per­con­duct­ing prop­er­ties. We have de­signed, built and tested a new fa­cil­ity for com­plex su­per­con­duct­ing thin film test­ing that in­cludes: (1) RRR mea­sure­ment with and with­out mag­netic field, (2) pla­nar and (3) tubu­lar mag­netic field pen­e­tra­tion ex­per­i­ments, (4) a su­per­con­duct­ing coax­ial res­onator for bulk nio­bium and su­per­con­duct­ing thin film char­ac­ter­i­sa­tion. The sys­tem is based on a closed cycle re­frig­er­a­tor, elim­i­nat­ing the need for liq­uid he­lium, thus mak­ing it sim­ple and safe to op­er­ate. The de­tails of the de­sign and com­mis­sion­ing will be pre­sented at the con­fer­ence.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL089  
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THPAL092 Test Particle Monte Carlo Simulation of NEG Coated Narrow Tubular Samples vacuum, ECR, simulation, SRF 3862
 
  • O. Seify, A.N. Hannah, O.B. Malyshev, Sirvinskaite, R. Sirvinskaite, R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • Sirvinskaite, R. Sirvinskaite
    Loughborough University, Loughborough, Leicestershire, United Kingdom
  
  The pump­ing prop­er­ties of the NEG coated vac­uum cham­bers play an im­por­tant role in the ef­fi­ciency of vac-uum sys­tem of ac­cel­er­a­tors. The stick­ing prob­a­bil­ity of the NEG films is one the most im­por­tant pa­ra­me­ters to char­ac­terise the pump­ing prop­er­ties of the NEG coated vac­uum cham­bers. In order to in­ves­ti­gate the NEG film stick­ing prob­a­bil­ity, Test Par­ti­cle Monte-Carlo (TPMC) mod­els were used. The mod­els were based on the de­sign of the in­stalled ex­per­i­men­tal setup in ASTeC Vac­uum Sci­ence group lab­o­ra­tory at Dares­bury Lab­o­ra­tory (DL). The re­sults of the sim­u­la­tions have been used for in­ter-pret­ing the re­sults of the mea­sure­ments in the ex­peri-men­tal setup.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL092  
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THPAL098 Pumping Properties of Single Metal Zirconium Non-Evaporable Getter Coating vacuum, target, site, injection 3869
 
  • Sirvinskaite, R. Sirvinskaite, M.D. Cropper, M.D. Cropper
    Loughborough University, Loughborough, Leicestershire, United Kingdom
  • A.N. Hannah, O.B. Malyshev, R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • O.B. Malyshev, R. Valizadeh
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Non-evap­orable get­ter (NEG) coat­ing has been used for years in many par­ti­cle ac­cel­er­a­tor fa­cil­i­ties due to its evenly dis­trib­uted pump­ing speed, low ther­mal out­gassing, and low pho­ton and elec­tron stim­u­lated des­orp­tion yields. We have pre­vi­ously demon­strated that qua­ter­nary Ti-Zr-Hf-V coat­ing de­posited from an alloy wire has the low­est des­orp­tion yields, the high­est stick­ing prob­a­bil­ity and sorp­tion ca­pac­ity. In this work, we ex­plore the sin­gle el­e­ment tar­gets which are widely avail­able and can be pro­duced in a form of a wire that is easy to apply for a uni­form coat­ing of var­i­ous shapes of vac­uum cham­ber. Sin­gle metal Zr coat­ings have been tested to find a more ef­fi­cient and cheaper way of pro­duc­ing the NEG-coated vac­uum cham­bers. Two sam­ples coated with Zr of dense and colum­nar struc­ture were analysed and re­sults of the pump­ing prop­er­ties are re­ported. The re­sults show that pure Zr coat­ing could be an eco­nomic so­lu­tion, de­spite not being as ef­fec­tive as can be achieved with qua­ter­nary NEG film. It shows that colum­nar Zr coat­ing can be ac­ti­vated and reaches full pump­ing ca­pac­ity at 160°C. This is close to the ac­ti­va­tion tem­per­a­ture of Ti-Zr-Hf-V and lower than that for the widely used ternary Ti-Zr-V alloy.  
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THPAL105 Lower Critical Field Measurement System of Thin Film Superconductor controls, simulation, SRF, embedded 3882
 
  • H. Ito
    Sokendai, Ibaraki, Japan
  • C.Z. Antoine
    CEA/IRFU, Gif-sur-Yvette, France
  • A. Four
    CEA/DRF/IRFU, Gif-sur-Yvette, France
  • H. Hayano, T. Kubo, T. Saeki
    KEK, Ibaraki, Japan
  • R. Ito, T. Nagata
    ULVAC, Inc, Chiba, Japan
  • Y. Iwashita, R. Katayama, H. Tongu
    Kyoto ICR, Uji, Kyoto, Japan
  • H. Oikawa
    Utsunomiya University, Utsunomiya, Japan
  
  Funding: The work is supported by Japan Society for the Promotion of Science Grant-in-Aid for Young Scientist (A) No.17H04839.
Su­per­con­duct­ing thin film is the promis­ing tech­nol­ogy to in­crease the per­for­mance of SRF cav­i­ties. The lower crit­i­cal field Hc1, which is one of the im­por­tant phys­i­cal pa­ra­me­ters char­ac­ter­iz­ing a su­per­con­duct­ing ma­te­r­ial, will be en­hanced by coat­ing Nb with thin film su­per­con­duc­tor such as NbN. To in­ves­ti­gate the per­for­mance of thin film, we de­vel­oped the Hc1 mea­sure­ment sys­tem using the third har­monic re­sponse of ap­plied AC mag­netic field. The mea­sure­ment sys­tem con­sists of he­lium cryo­stat with two of GM re­frig­er­a­tors, sam­ple Cu stage, so­le­noid coil Cu mount, so­le­noid coil, tem­per­a­ture sen­sors, and liq­uid he­lium level meter. AC mag­netic field is pro­duced by a coil which is dri­ven by func­tion gen­er­a­tor and power am­pli­fier at around 1 kHz. In order to con­trol the tem­per­a­ture of the sam­ple stage and coil mount, the depth of ther­mal an­chors at­tached to the stage and the mount can be moved by the motor. By this tem­per­a­ture con­trol the sam­ple state can be eas­ily trans­ferred from Meiss­ner state to mixed state. So that the mea­sure­ment is re­peated for var­i­ous ap­plied mag­netic field, and the tran­si­tion curve can be made. In this re­port, per­for­mance of the mea­sure­ment sys­tem is de­scribed. 		 
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THPAL114 The Analytical Model of the Helical Accelerating Structure of Linac with Helix Outside of the Vacuum Chamber vacuum, simulation, resonance, TRIUMF 3908
 
  • N.V. Avreline
    TRIUMF, Vancouver, Canada
  
  An an­a­lyt­i­cal model of the he­li­cal RF res­onator for the sin­gle charged 250 keV ni­tro­gen ion im­planter op­er­at­ing in CW was de­vel­oped. The an­a­lyt­i­cal model al­lowed to de­ter­mine the geom­e­try of the ac­cel­er­at­ing struc­ture and to con­struct CST Mi­crowave Stu­dio and ANSYS HFSS mod­els based on this an­a­lyt­i­cal model. Re­sults ob­tained from the an­a­lyt­i­cal model and sim­u­la­tions were within 5% of each other. The ex­per­i­men­tal in­ves­ti­ga­tion of the ac­cel­er­at­ing sec­tion con­firmed that the mod­els are cor­rect. The ac­cel­er­at­ing sec­tion was tuned and ver­i­fied for the right ac­cel­er­at­ing field dis­tri­b­u­tion and op­er­at­ing fre­quency. Fi­nally, the sec­tion was suc­cess­fully tested in 2 kW CW RF power.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL114  
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THPAL127 Structural Investigations of Nitrogen-Doped Niobium for Superconducting RF Cavities niobium, cavity, vacuum, ECR 3940
 
  • M. Major, L. Alff, M. Arnold, J. Conrad, S. Flege, R. Grewe, M. Mahr, N. Pietralla
    TU Darmstadt, Darmstadt, Germany
  • F. Hug
    KPH, Mainz, Germany
  
  Funding: Work supported by the German Federal Ministry for Education and Research (BMBF) through grant 05H15RDRBA.
Nio­bium is the stan­dard ma­te­r­ial for su­per­con­duct­ing RF (SRF) cav­i­ties. Su­per­con­duct­ing ma­te­ri­als with higher crit­i­cal tem­per­a­ture or higher crit­i­cal mag­netic field allow cav­i­ties to work at higher op­er­at­ing tem­per­a­tures or higher ac­cel­er­at­ing fields, re­spec­tively. En­hanc­ing the sur­face prop­er­ties of the su­per­con­duct­ing ma­te­r­ial in the range of the pen­e­tra­tion depth is also ben­e­fi­cial. One di­rec­tion of search for new ma­te­ri­als with bet­ter prop­er­ties is the mod­i­fi­ca­tion of bulk nio­bium by ni­tro­gen dop­ing. In the Nb-N phase di­a­gram the cubic delta-phase of NbN has the high­est crit­i­cal tem­per­a­ture (16 K). Al­ready slight ni­tro­gen dop­ing of the al­pha-Nb phase re­sults in higher qual­ity fac­tors.* Nb sam­ples were N-doped at the re­fur­bished UHV fur­nace at IKP Darm­stadt. Ref­er­ence sam­ples were an­nealed in 1 bar ni­tro­gen at­mos­phere at dif­fer­ent tem­per­a­tures. In this con­tri­bu­tion the re­sults on the struc­tural in­ves­ti­ga­tions (x-ray dif­frac­tion and pole fig­ure, sec­ondary ion mass spec­troscopy, scan­ning elec­tron mi­croscopy) at the Ma­te­ri­als Re­search De­part­ment of TU Darm­stadt will be pre­sented.
*Grassellino et al., Proc. SRF2015, MOBA06, 48. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL127  
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THPAL128 Autonomous Topography Detection and Traversal for an Inspection Robot Within the Beamline of Particle Accelerators vacuum, FEL, kicker, heavy-ion 3943
 
  • N. Schweizer
    Technische Universität Darmstadt (TU Darmstadt, RMR), Darmstadt, Germany
  • I. Pongrac
    GSI, Darmstadt, Germany
  
  Par­ti­cle ac­cel­er­a­tors fea­ture ul­tra-high vac­uum pipe sys­tems with unique topog­ra­phy, i.e. with a mul­ti­tude of dif­fer­ent vac­uum cham­bers of vary­ing di­men­sions and vary­ing pipe aper­tures. In order to be able to ex­am­ine the in­te­rior of the en­tire vac­uum sys­tem, even those parts which are not ac­ces­si­ble with­out dis­as­sem­bling large parts of the ac­cel­er­a­tor, a semi-au­tonomous robot is being de­vel­oped which shall tra­verse and vi­su­ally in­spect the vac­uum sys­tem of par­ti­cle ac­cel­er­a­tors. We pre­sent a generic con­cept based on dis­tance sen­sors for the in­spec­tion robot to de­tect steps be­tween vac­uum cham­bers and gaps in the beam­line. Move­ment strate­gies to au­tonomously over­come these basic ob­sta­cles are in­tro­duced. For eval­u­a­tion we use sim­u­la­tions of ideal en­vi­ron­ments with flat sur­faces as well as re­al­is­tic beam pipe en­vi­ron­ments of the SIS100 par­ti­cle ac­cel­er­a­tor. Ad­di­tion­ally, a pro­to­type of our robot con­cept con­firms the im­ple­men­ta­tion of all ma­neu­vers. Re­sults show that ob­sta­cles of pre­vi­ously un­known di­men­sions can be de­tected and re­li­ably tra­versed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL128  
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THPAL130 Effect of Deposition Temperature and Duration on Nb3Sn Diffusion Coating SRF, cavity, niobium, superconductivity 3950
 
  • U. Pudasaini, M.J. Kelley
    The College of William and Mary, Williamsburg, Virginia, USA
  • G.V. Eremeev, M.J. Kelley, C.E. Reece
    JLab, Newport News, Virginia, USA
  • M.J. Kelley, J. Tuggle
    Virginia Polytechnic Institute and State University, Blacksburg, USA
  
  Funding: Partially authored by Jefferson Science Associates under contract no. DE¬AC05¬06OR23177. Work at College of William & Mary supported by Office of High Energy Physics under grant SC0014475.
Nb3Sn is a po­ten­tial can­di­date to re­place Nb in SRF ac­cel­er­a­tor cav­i­ties to re­duce cost and ad­vance per­for-mance. Tin vapor dif­fu­sion is the pre­ferred tech­nique to re­al­ize such cav­i­ties by grow­ing a few mi­crons thick Nb3Sn coat­ing on the in­te­rior sur­face of the nio­bium cav­ity. The coat­ing process typ­i­cally uses tem­per­a­tures of 1100-1200 °C for 3-6 hours. It is im­por­tant to bet­ter un­der­stand the coat­ing process, and op­ti­mize the coat­ing pa­ra­me­ters to over­come the cur­rent lim­i­ta­tion on the per­for­mance of Nb3Sn coated SRF cav­i­ties. We in­vesti-gate Nb3Sn coat­ings pre­pared in the tem­per­a­ture range of 900-1200 °C and du­ra­tion of 3 - 12 hours using var­i­ous ma­te­r­ial char­ac­ter­i­za­tion tools. Vari­a­tion of these pa-ram­e­ters ap­pears to have no­table ef­fect on mi­crostruc­ture and topog­ra­phy of the ob­tained sur­face. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL130  
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THPAL131 Studies of Electropolishing and Oxypolishing Treated Diffusion Coated Nb3Sn Surfaces cavity, niobium, SRF, superconductivity 3954
 
  • U. Pudasaini, M.J. Kelley
    The College of William and Mary, Williamsburg, Virginia, USA
  • G.V. Eremeev, M.J. Kelley, C.E. Reece
    JLab, Newport News, Virginia, USA
  • M.J. Kelley, J. Tuggle
    Virginia Polytechnic Institute and State University, Blacksburg, USA
  
  The Nb3Sn-coated cav­i­ties aim to en­hance per­for-mance and sig­nif­i­cantly re­duce cost. Their fab­ri­ca­tion in­volves tin vapor dif­fu­sion coat­ing of Nb3Sn on the in­te­rior sur­face of a Nb cav­ity. Con­trolled re­moval of first few lay­ers to ob­tain a smoother and cleaner sur­face could be de­sir­able to im­prove the high field RF per­for-mance. Our first re­sults from the ap­pli­ca­tion of elec-trop­o­l­ish­ing and oxy­pol­ish­ing tech­niques on Nb3Sn-coated sur­faces in­di­cated re­duced sur­face rough­ness, and the sur­face com­po­si­tion ap­peared nom­i­nally un­changed. Sys­tem­atic stud­ies ex­plore the ef­fect of dif­fer­ent pol­ish-ing pa­ra­me­ters into the rough­ness and com­po­si­tion. We pre­sent the lat­est re­sults from SEM/EDS and AFM stud­ies of Nb3Sn-coated sam­ples treated with elec­trop­o­l­ish­ing and oxy­pol­ish­ing.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL131  
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THPAL133 LASE Surfaces for Mitigation of Electron Cloud in Accelerators electron, laser, vacuum, cavity 3958
 
  • B.S. Sian
    UMAN, Manchester, United Kingdom
  • O.B. Malyshev, R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  Vac­uum cham­ber sur­face char­ac­ter­is­tics such as the pho­ton and sec­ondary elec­tron yields (PEY and SEY) are crit­i­cal pa­ra­me­ters in the for­ma­tion of an elec­tron cloud, a se­ri­ous prob­lem that lim­its the per­for­mance of pro­ton and positron ac­cel­er­a­tors. A few years ago it was dis­cov­ered by the Vac­uum So­lu­tions Group at Dares­bury lab­o­ra­tory that Laser Ab­la­tion Sur­face En­gi­neer­ing (LASE) could pro­vide sur­faces with SEY<1 [1,2]. The LASE sur­faces are con­sid­ered as a base­line so­lu­tion for elec­tron cloud miti-gation in the Fu­ture Cir­cu­lar Col­lider (FCC). How­ever, these sur­faces are un­der­go­ing fur­ther op­ti­mi­sa­tion for the FCC ap­pli­ca­tion. While keep­ing SEY<1 the sur­faces should meet the fol­low­ing cri­te­ria: Low out­gassing, Low par­tic­u­late gen­er­a­tion and low sur­face re­sis­tance. In this paper we will re­port a num­ber of new sur­faces cre­ated using the LASE tech­nique with dif­fer­ent laser pa­ra­me­ters (wave­length, scan speed, pitch, rep­e­ti­tion rate, power, and pulse length) and their ef­fect on the SEY, sur­face re-sis­tance and vac­uum prop­er­ties, etc  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL133  
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THPAL149 RF System Based on Two Klystrons and Phase Modulation for Photo-Cathode Injector gun, klystron, linac, cathode 3996
 
  • P. Wang, D.Z. Cao, H.B. Chen, J. Shi, Z.H. Wang, H. Zha
    TUB, Beijing, People's Republic of China
  
  We pro­posed an RF sys­tem with two kly­strons, of which the pow­ers are com­bined by a 3dB-hy­brid. By man­ag­ing the phases of the two kly­strons re­spec­tively, the two pulses from the two out­put ports of the 3dB-hy­brid can be of dif­fer­ent pow­ers, phases, and shapes. One of the two pulses can be set to an RF gun, while the other one can feed trav­el­ing ac­cel­er­at­ing struc­tures. Two meth­ods of phase mod­u­la­tion were pro­posed based on this scheme. Com­par­ing with the state-of-art RF sys­tem, the new one can be of high ef­fi­ciency or can gen­er­ate elec­tron beams with higher en­ergy. The de­tailed analy­sis of the two meth­ods and some ex­per­i­ments are de­scribed in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL149  
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THPAL151 Progress in Understanding Breakdown Characteristics of X-Band Choke-Mode Structures timing, cavity, HOM, operation 4002
 
  • X.W. Wu, D.Z. Cao, H.B. Chen, J. Shi, H. Zha
    TUB, Beijing, People's Republic of China
  • T. Abe, T. Higo, S. Matsumoto
    KEK, Ibaraki, Japan
  
  Funding: National Natural Science Foundation of China (Grant No. 11135004).
As one of the higher-or­der-mode (HOM) damp­ing struc­tures, X-band choke-mode ac­cel­er­at­ing struc­tures had been stud­ied for sev­eral years. How­ever, the break­down char­ac­ter­is­tics of the X-band choke are still un­known. Five dif­fer­ent sin­gle-cell choke-mode ac­cel­er­at­ing struc­tures and one ref­er­ence struc­ture were de­signed, fab­ri­cated and high-gra­di­ent tested to study the re­lated RF break­down char­ac­ter­is­tics. The ab­sence of field emis­sion cur­rent flash was pro­posed to be the sign of break­downs oc­cur­ring in­side the choke, this was ver­i­fied by the post-mortem ob­ser­va­tion. Eval­u­a­tion of the break­down rate re­vealed that there is mem­ory ef­fect with pulse width and elec­tric field. The break­down rate in a sin­gle RF pulse did not have the 5th order pulse width and 30th order elec­tric field de­pen­dency pre­dicted by the em­pir­i­cal for­mula. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL151  
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THPAL154 High-Gradient Performance of X-Band Choke-Mode Structures ECR, GUI, HOM, damping 4011
 
  • X.W. Wu, D.Z. Cao, H.B. Chen, J. Shi, H. Zha
    TUB, Beijing, People's Republic of China
  • T. Abe, T. Higo, S. Matsumoto
    KEK, Ibaraki, Japan
  
  Funding: National Natural Science Foundation of China (Grant No. 11135004)
The choke-mode ac­cel­er­at­ing struc­ture is one of the higher-or­der-mode (HOM) damp­ing struc­tures. It has the ad­van­tage of rel­a­tively sim­ple fab­ri­ca­tion and low sur­face mag­netic field. C-band choke-mode ac­cel­er­at­ing struc­tures have been suc­cess­fully ap­plied in multi­bunch XFEL. How­ever, the X-band choke-mode study re­mains in the the­o­ret­i­cal de­sign stage. The high-gra­di­ent per­for­mance of the choke is still un­known. Five dif­fer­ent sin­gle-cell choke-mode ac­cel­er­at­ing struc­tures were de­signed, fab­ri­cated and high-gra­di­ent tested to study the re­lated RF break­down char­ac­ter­is­tics. It was ob­served that high elec­tric field and small choke di­men­sion caused se­ri­ous break­downs in the choke which was the main lim­i­ta­tion of the high-gra­di­ent per­for­mance. The Choke-mode ac­cel­er­at­ing struc­tures reached 130 MV/m by de­creas­ing the elec­tric field and in­creas­ing the choke gap. A new quan­tity was pro­posed to give the high-gra­di­ent per­for­mance limit of choke-mode ac­cel­er­at­ing struc­tures due to RF break­down. The new quan­tity was ob­tained from the sum­mary of the high-gra­di­ent ex­per­i­ments and could be used to guide high-gra­di­ent choke-mode ac­cel­er­at­ing struc­ture de­sign. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL154  
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THPAL157 Investigation of Transverse Wakefield and Beam Break Up Effect in Irradiation Linacs cavity, wakefield, linac, simulation 4020
 
  • X.C. Meng, H.B. Chen, J. Shi, Z.H. Wang, H. Zha, S.X. Zheng
    TUB, Beijing, People's Republic of China
  • G.H. Li, J.S. Liu, Y.H. Liu
    NUCTECH, Beijing, People's Republic of China
  
  Study of beam break up ef­fect in linacs has been done in re­cent years. The beam-in­duced high order dipo­lar modes, es­pe­cially the TM11-like mode were in­ves­ti­gated for the linacs both in trav­el­ling wave and back­ward trav-elling wave. Mea­sure­ments of beam-break up in a travel-ling wave linac were car­ried out and re­sults are dis­cussed. More­over, a the­o­ret­i­cal model was de­vel­oped for the ir­ra­di­a­tion linacs to study the de­tailed in­ter­ac­tion be-tween the trans­verse wake­field and the elec­tron beam.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL157  
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THPMF011 Femtosecond Laser Ablation for Manufacturing of X-ray Lenses and Phase Corrector Plates optics, laser, photon, storage-ring 4057
 
  • S.P. Antipov
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • L. Assoufid, W.C. Grizolli, J. Qian, X. Shi
    ANL, Argonne, Illinois, USA
  
  Funding: DOE SBIR
The next gen­er­a­tion light sources such as dif­frac­tion lim­ited stor­age rings and high rep­e­ti­tion rate free elec­tron lasers (FELs) will gen­er­ate X-ray beams with sig­nif­i­cantly in­creased peak and av­er­age bril­liance. These fu­ture fa­cil­i­ties will re­quire X-ray op­ti­cal com­po­nents ca­pa­ble of han­dling large in­stan­ta­neous and av­er­age power den­si­ties while tai­lor­ing the prop­er­ties of the X-ray beams for a va­ri­ety of sci­en­tific ex­per­i­ments. In this paper we re­port on re­search and de­vel­op­ment of a sin­gle crys­tal di­a­mond com­pound re­frac­tive lens. Di­a­mond lenses pre­sented here are fab­ri­cated by fs-laser cut­ting and sub­se­quent pol­ish­ing. Grat­ing in­ter­fer­om­e­try mea­sure­ment data of these lenses had been per­formed at the Ad­vanced Pho­ton Source (Ar­gonne). Be­sides the lenses, we fab­ri­cated and tested sev­eral phase cor­rec­tion plates, a re­frac­tive el­e­ments de­signed to cor­rect for cu­mu­la­tive X-ray beam aber­ra­tions. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF011  
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THPMF014 First Experiments at the CLEAR User Facility electron, radiation, operation, plasma 4066
 
  • R. Corsini, A. Curcio, S. Curt, S. Döbert, W. Farabolini, D. Gamba, R. Garcia Alia, T. Lefèvre, G. McMonagle, P.K. Skowroński, M. Tali, F. Tecker
    CERN, Geneva, Switzerland
  • E. Adli, C.A. Lindstrøm, K.N. Sjobak
    University of Oslo, Oslo, Norway
  • R.M. Jones, A. Lagzda
    UMAN, Manchester, United Kingdom
  
  The new "CERN Lin­ear Elec­tron Ac­cel­er­a­tor for Re­search" (CLEAR) fa­cil­ity at CERN started its op­er­a­tion in fall 2017. CLEAR re­sults from the con­ver­sion of the CAL­IFES beam line of the for­mer CLIC Test Fa­cil­ity (CTF3) into a new test­bed for gen­eral ac­cel­er­a­tor R&D and com­po­nent stud­ies for ex­ist­ing and pos­si­ble fu­ture ac­cel­er­a­tor ap­pli­ca­tions. CLEAR can pro­vide a sta­ble and re­li­able elec­tron beam from 60 to 220 MeV in sin­gle or multi bunch con­fig­u­ra­tion at 1.5 GHz. The ex­per­i­men­tal pro­gram in­cludes stud­ies for high gra­di­ent ac­cel­er­a­tion meth­ods, e.g. for CLIC X-band and plasma tech­nol­ogy, pro­to­typ­ing and val­i­da­tion of ac­cel­er­a­tor com­po­nents, e.g. for the HL-LHC up­grade, and ir­ra­di­a­tion test ca­pa­bil­i­ties for char­ac­ter­i­za­tion of elec­tronic com­po­nents and for med­ical ap­pli­ca­tions. An overview of the fa­cil­ity ca­pa­bil­i­ties and a sum­mary of the lat­est re­sults will be pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF014  
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THPMF024 Commissioning and Operation of FAST Electron Linac at Fermilab cavity, electron, cryomodule, MMI 4096
 
  • A.L. Romanov, C.M. Baffes, D.R. Broemmelsiek, K. Carlson, D.J. Crawford, N. Eddy, D.R. Edstrom, E.R. Harms, J. Hurd, M.J. Kucera, J.R. Leibfritz, I.L. Rakhno, J. Reid, J. Ruan, J.K. Santucci, V.D. Shiltsev, G. Stancari, R.M. Thurman-Keup, A. Valishev, A. Warner
    Fermilab, Batavia, Illinois, USA
  
  We re­port re­sults of the beam com­mis­sion­ing and first op­er­a­tion of the 1.3 GHz su­per­con­duct­ing RF elec­tron lin­ear ac­cel­er­a­tor at Fer­mi­lab Ac­cel­er­a­tor Sci­ence and Tech­nol­ogy (FAST) fa­cil­ity. Con­struc­tion of the linac was com­pleted and the ma­chine was com­mis­sioned with beam in 2017. The max­i­mum total beam en­ergy of about 300 MeV was achieved with the record en­ergy gain of 250 MeV in the ILC-type SRF cry­omod­ule. The pho-toin­jec­tor was tuned to pro­duce trains of 200 pC bunches with a fre­quency of 3 MHz at a rep­e­ti­tion rate of 1 Hz. This re­port de­scribes the as­pects of ma­chine com­mis­sion-ing such as tun­ing of the SRF cry­omod­ule and beam op­tics op­ti­miza­tion. We also pre­sent high­lights of an ex­per­i­men­tal pro­gram car­ried out par­a­sit­i­cally dur­ing the two-month run, in­clud­ing stud­ies of wake-fields, and ad­vanced beam phase space ma­nip­u­la­tion.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF024  
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THPMF048 Bunch Length Measurements Using CTR at the AWA with Comparison to Simulation simulation, laser, gun, electron 4166
 
  • N.R. Neveu
    IIT, Chicago, Illinois, USA
  • S.P. Antipov
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • A. Halavanau, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • P. Piot
    Fermilab, Batavia, Illinois, USA
  • J.G. Power, C. Whiteford, E.E. Wisniewski
    ANL, Argonne, Illinois, USA
  • L.K. Spentzouris
    Illinois Institute of Technology, Chicago, Illinois, USA
  
  Funding: This work is funded by the DOE Office of Science, grant no. DE-SC0015479, and contract No. DE-AC02- 06CH11357.
In this paper we pre­sent elec­tron bunch length mea­sure­ments at the Ar­gonne Wake­field Ac­cel­er­a­tor (AWA) pho­toin­jec­tor fa­cil­ity. The AWA ac­cel­er­a­tor has a large dy­namic charge den­sity range, with elec­tron beam charge vary­ing be­tween 0.1 nC - 100 nC, and laser spot size di­am­e­ter at the cath­ode be­tween 0.1 mm - 18 mm. The bunch length mea­sure­ments were taken at dif­fer­ent charge den­si­ties using a metal­lic screen and a Mar­tin-Pu­plett in­ter­fer­om­e­ter to per­form au­to­cor­re­la­tion scans of the cor­re­spond­ing co­her­ent tran­si­tion ra­di­a­tion (CTR). A liq­uid he­lium-cooled 4K bolome­ter was used to reg­is­ter the in­ter­fer­om­e­ter sig­nal. The ex­per­i­men­tal re­sults are com­pared with Im­pact-T and OPAL-T nu­mer­i­cal sim­u­la­tions. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF048  
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THPMF049 Photoinjector Optimization Studies at the AWA simulation, emittance, laser, gun 4169
 
  • N.R. Neveu
    IIT, Chicago, Illinois, USA
  • J. Larson, J.G. Power
    ANL, Argonne, Illinois, USA
  • L.K. Spentzouris
    Illinois Institute of Technology, Chicago, Illinois, USA
  
  Funding: This work is funded by the DOE Office of Science, grant no. DE-SC0015479, and contract No. DE-AC02- 06CH11357.
With a vari­able charge range of 0.1 nC - 100 nC, the Ar­gonne Wake­field Ac­cel­er­a­tor fa­cil­ity (AWA) has a unique and dy­namic set of op­er­at­ing pa­ra­me­ters. Ad­just­ment of the op­tics and oc­ca­sion­ally the rf phases is re­quired each time the bunch charge is changed. Presently, these ad­just­ments are done by the op­er­a­tor dur­ing each ex­per­i­ment. This is time con­sum­ing and in­ef­fi­cient, more so at high charge and for com­plex ex­per­i­men­tal set ups. In an at­tempt to re­duce the amount of time spent ad­just­ing pa­ra­me­ters by hand, sev­eral op­ti­miza­tion meth­ods in sim­u­la­tion are being ex­plored. This in­cludes using the well-known Ge­netic Al­go­rithm (NSGA-II), in­cor­po­rated into OPAL-T. We have also in­ves­ti­gated a model-based method and novel struc­ture based al­go­rithms de­vel­oped at ANL. On­go­ing ef­forts in­clude using these op­ti­miza­tion meth­ods to im­prove op­er­a­tions at the AWA. Sim­u­la­tion re­sults will be com­pared to mea­sured beam pa­ra­me­ters at the AWA, and one op­ti­miza­tion method will be se­lected for use in guid­ing op­er­a­tions going for­ward. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF049  
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THPMF063 The MESA 15 kW cw 1.3 GHz Solid State Power Amplifier Prototype operation, SRF, linac, cavity 4216
 
  • R.G. Heine, F. Fichtner
    IKP, Mainz, Germany
  
  The Mainz En­ergy re­cov­er­ing Su­per­con­duct­ing Ac­cel­er­a­tor MESA is a multi-turn en­ergy re­cov­ery linac with beam en­er­gies in the 100 MeV regime cur­rently de­signed and build at In­sti­tut für Kern­physik (KPH) of Jo­hannes Guten­berg-Uni­ver­sität Mainz. The main ac­cel­er­a­tor con­sists of two su­per­con­duct­ing Rossendorf type mod­ules, while the in­jec­tor MAMBO (Mil­liAMpere BOoster) re­lies on nor­mal con­duct­ing tech­nolgy. The high power RF sys­tem is planned com­pletely in solid state tech­nol­ogy. With the high power de­mands of the nor­mal con­duct­ing RF cav­i­ties up-to-date tran­sis­tor tech­nol­ogy with in­creased power den­sity has to be used. A 15 kW CW power ampi­fier pro­to­type with the new tech­nol­ogy has been de­vel­oped by Sigma Phi Elec­tron­ics and de­liverd to KPH. In this paper we will pre­sent the re­sults of the per­for­mance mea­sure­ments of the am­pli­fier.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF063  
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THPMF068 Commissioning Status of FLUTE gun, electron, laser, MMI 4229
 
  • A. Malygin, A. Bernhard, E. Bründermann, A. Böhm, S. Funkner, S. Marsching, W. Mexner, A. Mochihashi, A.-S. Müller, M.J. Nasse, G. Niehues, R. Ruprecht, T. Schmelzer, M. Schuh, N.J. Smale, P. Wesolowski, M. Yan
    KIT, Karlsruhe, Germany
  • I. Križnar
    Cosylab, Ljubljana, Slovenia
  • M. Schwarz
    CERN, Geneva, Switzerland
  
  FLUTE (Fer­n­in­frarot Linac- Und Test-Ex­per­i­ment) will be a new com­pact ver­sa­tile lin­ear ac­cel­er­a­tor at the KIT. Its pri­mary goal is to serve as a plat­form for a va­ri­ety of ac­cel­er­a­tor stud­ies as well as to gen­er­ate strong ul­tra-short THz pulses for pho­ton sci­ence. The phase I of the pro­ject, which in­cludes the RF photo in­jec­tor pro­vid­ing elec­trons at beam en­ergy of 7 MeV and a cor­re­spond­ing di­ag­nos­tics sec­tion, is cur­rently being com­mis­sioned. In this con­tri­bu­tion, we re­port on the lat­est progress of the com­mis­sion­ing phase. The sta­tus of the gun con­di­tion­ing will be given, fol­lowed by an overview of the RF sys­tem and the laser sys­tem.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF068  
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THPMF072 Implementation of Ultra-Low Frequency Non-Linear Raman Spectroscopy with the Gun Laser at FLUTE scattering, laser, gun, optics 4242
 
  • S. Funkner, E. Bründermann, A.-S. Müller, M.J. Nasse, G. Niehues, T. Schmelzer, J.L. Steinmann, M. Yan
    KIT, Eggenstein-Leopoldshafen, Germany
  • M. Tani
    University of Fukui, Fukui, Japan
  
  At the Karl­sruhe In­sti­tute of Tech­nol­ogy (KIT) the new com­pact ver­sa­tile lin­ear ac­cel­er­a­tor FLUTE is cur­rently under com­mis­sion­ing. This ac­cel­er­a­tor will pro­vide in­tense broad­band THz pulses for spec­tro­scopic ex­per­i­ments. Here, we demon­strate the im­ple­men­ta­tion of a co­her­ent Raman spec­trom­e­ter using the RF gun laser of FLUTE. With our ex­per­i­ment, we can mea­sure the Raman spec­trum at ul­tra-low fre­quen­cies. The mea­sure­ment prin­ci­ple, which was re­cently pub­lished, is based on co­her­ent non­lin­ear ex­ci­ta­tion of the ob­served sam­ple. The spec­trom­e­ter con­sists of a stretcher and an in­ter­fer­om­e­ter, which can be sim­ply built from stan­dard op­tics. We will show that the ac­ces­si­ble spec­tral range over­laps well with that from the THz pulses of the planned FLUTE ex­per­i­ment. Thus, the co­her­ent Raman ex­per­i­ment can pro­vide spec­tral in­for­ma­tion com­ple­men­tary to ab­sorp­tion spec­tral mea­sure­ments using the THz ra­di­a­tion of FLUTE.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF072  
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THPMK023 Coherent Transition Radiation Generated from Transverse Electron Density Modulation radiation, electron, detector, simulation 4348
 
  • A. Halavanau, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • A.I. Benediktovitch
    BSU, Minsk, Belarus, Belarus
  • S.N. Galyamin, A.V. Tyukhtin
    Saint Petersburg State University, Saint Petersburg, Russia
  • P. Piot
    Fermilab, Batavia, Illinois, USA
  
  Co­her­ent Tran­si­tion ra­di­a­tion (CTR) of a given fre­quency is com­monly gen­er­ated with lon­gi­tu­di­nal elec­tron bunch trains. In this paper we pre­sent a study of CTR pro­duc­tion from elec­tron trans­verse den­sity mod­u­la­tion. We demon­strate via nu­mer­i­cal sim­u­la­tions a sim­ple tech­nique to gen­er­ate THz-scale fre­quen­cies from mm-scale trans­versely sep­a­rated elec­tron beam­lets. The re­sults and a po­ten­tial ex­per­i­men­tal setup are dis­cussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK023  
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THPMK062 Transverse Energy Distribution Measurements for Polycrystalline and (100) Copper Photocathodes with Known Levels of Surface Roughness cathode, electron, emittance, detector 4438
 
  • L.B. Jones, B.L. Militsyn, T.C.Q. Noakes
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • L.B. Jones, D.P. Juarez-Lopez, B.L. Militsyn, T.C.Q. Noakes, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • D.P. Juarez-Lopez, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  
  Funding: This work is part of EuCARD-2, partly-funded by the European Commission, GA 312453.
The min­i­mum achiev­able emit­tance in an elec­tron ac­cel­er­a­tor de­pends strongly on the in­trin­sic emit­tance of the pho­to­cath­ode elec­tron source. This is mea­sure­able as the mean lon­gi­tu­di­nal and trans­verse en­ergy spreads in the pho­toemit­ted elec­trons. ASTeC's Trans­verse En­ergy Spread Spec­trom­e­ter (TESS)* ex­per­i­men­tal fa­cil­ity can be used with III-V semi­con­duc­tor, multi-al­kali and metal pho­to­cath­odes to mea­sure trans­verse and lon­gi­tu­di­nal en­ergy dis­tri­b­u­tions. Our R&D fa­cil­i­ties also in­clude in-vac­uum quan­tum ef­fi­ciency mea­sure­ment, XPS, STM, plus ex-vac­uum op­ti­cal and STM mi­croscopy for sur­face metrol­ogy. In­trin­sic emit­tance is strongly af­fected by the pho­to­cath­ode sur­face rough­ness**, and the de­vel­op­ment of tech­niques to man­u­fac­ture the smoothest pho­to­cath­ode is a pri­or­ity for the elec­tron source com­mu­nity. We pre­sent en­ergy dis­tri­b­u­tion mea­sure­ments for elec­trons emit­ted from cop­per pho­to­cath­odes with both de­fined sin­gle-crys­tal (100) and poly­crys­talline sur­faces with mea­sured lev­els of sur­face rough­ness.
* Proc. FEL'13, TUPPS033, pp. 290-293.
** Proc. FEL'06, THPPH013, pp. 583-586. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK062  
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THPMK077 The Preliminary Experiment Studies for Soft X-Ray Self-Seeding System Design of SCLF Facility photon, FEL, simulation, electron 4481
 
  • K.Q. Zhang, C. Feng, D. Wang, Z.T. Zhao
    SINAP, Shanghai, People's Republic of China
  
  The pre­lim­i­nary ex­per­i­ment stud­ies for soft x-ray self-seed­ing sys­tem de­sign of SCLF fa­cil­ity have been pre-sented in this paper. Some prac­ti­cal prob­lems and pre-en­gi­neer­ing de­sign have been stud­ied for the ex­per­i­men­tal pre­pare of soft x-ray self-seed­ing for the fu­ture SCLF fa­cil­ity. The mono­chro­ma­tor sys­tem de­signs in this paper in­clude op­ti­cal struc­ture, op­ti­cal pa­ra­me­ters and me­chan­i­cal de­sign. The de­signed op­ti­cal sys­tem has an op­ti­cal res­o­lu­tion of 1/10000 at the pho­ton en­ergy of 700-1300eV based on the op­ti­cal sim­u­la­tion. To make the sys­tem sat­isfy the ex­per­i­men­tal re­quire­ments, me­chan­i­cal in­stall re­quire­ments and in­stall pre­ci­sions are also analysed. Con­sid­er­ing the ac­tual varies er­rors, the er­rors analy­ses such as the sur­face er­rors of the op­ti­cal mir­ror and the ma­chin­ing er­rors of the VLS grat­ing are also car­ried out. In con­clu­sion, pre­lim­i­nary ex­per­i­men­tal stud­ies in­clud­ing sys­tem de­sign and varies en­gi­neer­ing re­quire­ments are in­tro­duced to make sure that the pre­sented de­sign is re­li­able for final soft x-ray self-seed­ing ex­per­i­ment of SCLF fa­cil­ity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK077  
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THPMK094 Thermal Design of a 100 kW Electron to Gamma Converter at TRIUMF electron, target, TRIUMF, ISOL 4520
 
  • B.G. Cade, L. Egoriti, A. Gottberg
    TRIUMF, Vancouver, Canada
  • D.R. Priessl
    UVIC, Victoria, Canada
  
  The elec­tron tar­get sta­tion (AETE) of the TRI­UMF-ARIEL Fa­cil­ity will em­ploy an elec­tron "dri­ver" beam to ir­ra­di­ate Iso­tope Sep­a­ra­tor On-Line (ISOL) tar­gets for the pro­duc­tion of ra­dioac­tive iso­topes via photofis­sion. 30 MeV elec­trons will be con­verted to gamma spec­trum Bremsstrahlung pho­tons via an elec­tron to gamma (e-y) con­verter lo­cated up­stream of the ISOL tar­get. The e-y con­cept uses a com­pos­ite metal with two lay­ers: One high-Z ma­te­r­ial to con­vert elec­trons to pho­tons, and one low-Z ma­te­r­ial to pro­vide struc­tural sup­port, ther­mal dis­si­pa­tion, and max­i­mal trans­parency to the pro­duced gamma pho­tons. Sev­eral ma­te­r­ial com­bi­na­tions and bond­ing processes are cur­rently being eval­u­ated and tested using TRI­UMF's E-LINAC. Wa­ter-cool­ing and ther­mal de­sign are being op­ti­mized for 100 kW op­er­a­tion and have thus far been val­i­dated up to 10 kW dri­ver beam power. The lat­est test re­sults and fu­ture prospects are sum­ma­rized.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK094  
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THPMK099 Measurement of the Laser-Induced Energy Modulation Amplitude at the Short-Pulse Facility at DELTA laser, electron, radiation, synchrotron 4538
 
  • A. Meyer auf der Heide, B. Büsing, S. Khan, N.M. Lockmann, C. Mai, B. Riemann, B. Sawadski
    DELTA, Dortmund, Germany
  
  The short-pulse fa­cil­ity at the syn­chro­tron light source DELTA op­er­ated by the TU Dort­mund Uni­ver­sity em­ploys co­her­ent har­monic gen­er­a­tion (CHG) to pro­vide ul­tra­short pulses in the vac­uum ul­tra­vi­o­let and ter­a­hertz regime. Here, a laser-elec­tron in­ter­ac­tion re­sults in a mod­u­la­tion of the elec­tron en­ergy which is trans­formed into a den­sity mod­u­la­tion by a mag­netic chi­cane. Mea­sure­ments of the en­ergy mod­u­la­tion am­pli­tude with dif­fer­ent tech­niques in­clud­ing an RF phase mod­u­la­tion are pre­sented. A com­bi­na­tion of the re­sults allow to es­ti­mate the en­ergy spread of the elec­tron beam.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK099  
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THPMK111 Negative Electron Affinity Gallium Arsenide Photocathodes Based on Optically Resonant Nanostructure cathode, resonance, electron, simulation 4575
 
  • S. Zhang, M. Poelker, M.L. Stutzman
    JLab, Newport News, Virginia, USA
  • X. Peng, J. Zou
    East China University of Science and Technology, Shanghai, People's Republic of China
  
  Funding: DOE
We re­port the de­sign and fab­ri­ca­tion of a new type of neg­a­tive elec­tron affin­ity (NEA) gal­lium ar­senide (GaAs) pho­to­cath­ode with op­ti­cally res­o­nant nanos­truc­tures. We ob­served a sig­nif­i­cant en­hance­ment of the quan­tum effi-ciency (QE) from the GaAs pho­to­cath­ode with nanowire ar­rays (NWA) due to the Mie res­o­nance ef­fect within the in­tended wave­length range. The­o­ret­i­cal cal­cu­la­tions of the ex­pected re­flectance be­hav­iour to­gether with ex­peri-men­tal re­sults of op­ti­cal and pho­toe­mis­sion char­ac­teris-tics are pre­sented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK111  
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THPMK113 From Coherent Harmonic Generation to Steady State Microbunching storage-ring, bunching, radiation, electron 4583
 
  • X.J. Deng, W.-H. Huang, T. Rui, C.-X. Tang
    TUB, Beijing, People's Republic of China
  • A. Chao, D.F. Ratner
    SLAC, Menlo Park, California, USA
  • J. Feikes, M. Ries
    HZB, Berlin, Germany
  • R. Klein
    PTB, Berlin, Germany
  
  Steady state mi­crobunch­ing (SSMB) is an elec­tron stor­age ring based scheme pro­posed by Rat­ner and Chao to gen­er­ate high av­er­age power nar­row band co­her­ent ra­di­a­tion with wave­length rang­ing from THz to EUV. One key step to­wards open­ing up the po­ten­tial of SSMB is the ex­per­i­men­tal proof of the SSMB prin­ci­ple. In this paper, the SSMB ex­per­i­ment planned and pre­pared by a re­cently es­tab­lished col­lab­o­ra­tion is pre­sented start­ing from a mod­i­fied co­her­ent har­monic gen­er­a­tion (CHG). Sin­gle par­ti­cle dy­nam­ics of mi­crobunch­ing in an elec­tron stor­age ring are an­a­lyzed. Though ori­ented for CHG and SSMB, some of the ef­fects an­a­lyzed are also im­por­tant in cases like bunch slic­ing, bunch com­pres­sion, FEL beam trans­port lines etc, in which pre­cise lon­gi­tu­di­nal phase space ma­nip­u­la­tions are in­volved. These dy­nam­ics to­gether with some SSMB re­lated col­lec­tive ef­fects are to be in­ves­ti­gated on the stor­age ring MLS in Berlin.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK113  
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THPMK115 Optical Cavity R&D for Laser-Electron Interaction Applications cavity, laser, HOM, electron 4587
 
  • X. Liu, W.-H. Huang, C.-X. Tang, L.X. Yan
    TUB, Beijing, People's Republic of China
  • R. Chiche, K. Dupraz, P. Favier, A. Martens, H. Monard, Z.F. Zomer
    LAL, Orsay, France
  • D. Nutarelli
    LAC, Orsay, France
  
  Laser-elec­tron In­verse Comp­ton Scat­ter­ing X-ray source based on op­ti­cal en­hance­ment cav­ity is ex­pected to pro­duce higher-flux and bet­ter-qual­ity X-rays than con­ven­tional sources, in ad­di­tion, to be­come more com­pact, much cheaper than Free Elec­tron Laser and Syn­chro­tron Ra­di­a­tion. One X-ray source named ThomX is under con­struc­tion at LAL, France. An elec­tron stor­age ring with 50 MeV, 16.7 MHz elec­tron beam will col­lide with a few pi­cosec­ond pulsed laser to pro­duce 1013 pho­tons per sec­ond. A pro­to­type cav­ity with a high fi­nesse (F=25,100) in the pi­cosec­ond regime is used to per­form R & D for ThomX. We ob­tained 380 kW power stored in the op­ti­cal cav­ity and mode in­sta­bil­i­ties were ob­served. The EOM-based fre­quency mod­u­la­tion to mea­sure the fi­nesse, the in­flu­ence of dust on fi­nesse, high-power ex­per­i­ments and other re­lated is­sues are men­tioned briefly. We will also de­scribe the TTX2 (Ts­inghua Thom­son Scat­ter­ing X-ray source) at Ts­inghua Uni­ver­sity which is in de­sign process. TTX2 prefers using an elec­tron stor­age ring and an op­ti­cal cav­ity in order to get high X-ray flux.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK115  
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THPMK116 NEA Surface Activation of GaAs Photocathode with CO2 cathode, electron, ECR, emittance 4590
 
  • L.Guo. Guo
    UVSOR, Okazaki, Japan
  • H. Iijima
    Tokyo University of Science, Tokyo, Japan
  • M. Kuriki
    HU/AdSM, Higashi-Hiroshima, Japan
  • K. Uchida
    Cosylab Japan, Ibaraki, Japan
  
  NEA (neg­a­tive elec­tron affin­ity)-GaAs cath­ode is able to gen­er­ate highly spin po­lar­ized elec­tron beam more than 90%. The NEA ac­ti­va­tion is per­formed usu­ally with Cs and O2 or NF3, but the exact struc­ture of the NEA sur­face is not known. In this paper, we per­formed the NEA ac­ti­va­tion on a cleaned GaAs sur­face with CO2, CO, N2, and O2 gases and com­pared the re­sults to im­prove our un­der­stand­ing on the NEA sur­face. We found that CO2 ac­ti­vated the cath­ode, but N2 and CO did not. By an­a­lyz­ing CO2 ac­ti­va­tion, we found that atomic oxy­gen ac­ti­vates the NEA sur­face and CO de­grades the NEA sur­face si­mul­ta­ne­ously. We found that the NEA ac­ti­va­tion abil­ity of atomic oxy­gen is al­most a half of that of O2 mol­e­cule.*
*L. Guo, M. Kuriki, H. Iijima, K. Uchida. "NEA surface activation of GaAs photocathode with different gases", Surface Science 664C (2017) pp. 65-69. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK116  
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THPMK118 GaN Thin Film Photocathodes for High Brightness Electron Beams cathode, electron, target, brightness 4594
 
  • M. Vogel, X. Jiang, M. Schumacher
    University Siegen, Siegen, Germany
  
  Funding: This work was supported by the German Federal Ministry of Education and Research under grant 05K16PS1 "HOPE II: Hochbrillante photoinduzierte Hochfrequenz-Elektronenquellen".
Gal­lium ni­tride (GaN) is one promis­ing can­di­date as pho­to­cath­ode ma­te­r­ial show­ing high quan­tum ef­fi­cien­cies which is one of the re­quire­ments for high bright­ness elec­tron beams. In ad­di­tion to re­ported quan­tum ef­fi­cien­cies of up to 70%, GaN needs to sat­isfy the de­mands for long life­time, low dark cur­rent and low ther­mal emit­tance. In this con­tri­bu­tion, the on­go­ing ac­tiv­i­ties of the syn­the­sis by means of re­ac­tive rf mag­netron sput­ter­ing and char­ac­ter­i­za­tion of GaN is pre­sented. The lat­ter is done by stan­dard ma­te­ri­als sci­ence meth­ods and in-situ mea­sure­ments of the quan­tum ef­fi­ciency in com­bi­na­tion with life­time and dark cur­rent mea­sure­ments to asses and op­ti­mize the pho­to­cath­ode's per­for­mance. Along with the pro­ject's de­tails, first ex­per­i­men­tal re­sults of GaN thin films syn­the­sized uti­liz­ing a GaAs source are pre­sented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK118  
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THPMK147 Measurement of Slice-Emittance of Electron Bunch Using RF Transverse Deflector emittance, injection, acceleration, electron 4648
 
  • T. Sasaki, Y. Nakazato, M. Washio
    Waseda University, Tokyo, Japan
  • Y. Koshiba
    RISE, Tokyo, Japan
  • K. Sakaue
    Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
  
  We have been study­ing a com­pact elec­tron ac­cel­er­a­tor based on an S-band Cs-Te pho­to­cath­ode rf elec­tron gun at Waseda Uni­ver­sity. We are ap­ply­ing this high qual­ity elec­tron beam to soft X-ray gen­er­a­tion, co­her­ent THz wave gen­er­a­tion and pulse ra­di­ol­y­sis ex­per­i­ment. In these ap­pli­ca­tions, lon­gi­tu­di­nal pa­ra­me­ters of the elec­tron beam are im­por­tant. Thus, we de­vel­oped the RF de­flect­ing cav­ity which can di­rectly con­vert lon­gi­tu­di­nal dis­tri­b­u­tion of the beam to trans­verse with high tem­po­ral res­o­lu­tion, and suc­ceeded in mea­sur­ing lon­gi­tu­di­nal pro­file of an elec­tron beam from the RF gun. En­cour­aged by these suc­cess­ful re­sults, we started to mea­sure slice emit­tance. Slice emit­tance would be very use­ful for im­prov­ing the RF elec­tron gun cav­ity. There­fore, we tried to mea­sure the slice emit­tance of the elec­tron beam by ap­ply­ing the Q-scan method to de­flected beam by RF de­flect­ing cav­ity. In this con­fer­ence, we will re­port the prin­ci­ple, ex­per­i­men­tal re­sults of the slice emit­tance mea­sure­ment, and fu­ture prospects.
C. Vaccarezza et al., "Slice emittance measurements at SPARC photoinjector with a RF deflector", Proc. of EPAC08, Genoa, Italy 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK147  
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THPML007 An Investigation of Electron Beam Divergence from a Single DFEA Emitter Tip cathode, electron, laser, emittance 4662
 
  • H.L. Andrews, B.K. Choi, R.L. Fleming, D. Kim, J.W. Lewellen, K.E. Nichols, D.Y. Shchegolkov, E.I. Simakov
    LANL, Los Alamos, New Mexico, USA
  
  Funding: We gratefully acknowledge the support of the U.S. Department of Energy through the LANL/LDRD Program for this work.
Di­a­mond Field-Emit­ter Array (DFEA) cath­odes are ar­rays of mi­cron-scale di­a­mond pyra­mids with nanome­ter-scale tips. DFEAs can pro­duce high emis­sion cur­rents with small emit­tance and en­ergy spread. At LANL, we have an on­go­ing pro­gram to test DFEA cath­odes for the pur­pose of using them to gen­er­ate high-cur­rent, low-emit­tance elec­tron beams for di­elec­tric laser ac­cel­er­a­tors. We have re­cently up­graded our cath­ode test cham­ber to use a mesh anode in place of a solid lu­mi­nes­cent anode. In ad­di­tion to al­low­ing for down­stream beam trans­port, this arrange­ment may elim­i­nate ear­lier prob­lems with re­duced cath­ode per­for­mance due to ion back-bom­bard­ment. We are mea­sur­ing di­ver­gence of the elec­tron beam past the mesh in an ef­fort to char­ac­ter­ize the in­her­ent beam di­ver­gence off the di­a­mond tip and di­ver­gence con­tri­bu­tion from the mesh. We will com­pare these ob­ser­va­tions with the­o­ret­i­cal and mod­eled val­ues. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML007  
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THPML010 Modeling of Diamond Field Emitter Arrays for Shaped Electron Beam Production electron, simulation, gun, emittance 4668
 
  • K.E. Nichols, H.L. Andrews, D.Y. Shchegolkov, E.I. Simakov
    LANL, Los Alamos, New Mexico, USA
  
  We pre­sent sim­u­la­tions of shaped elec­tron beam pro­duc­tion from di­a­mond field emit­ter array (DFEA) cath­odes. DFEAs are ar­rays of di­a­mond pyra­mids with bases of the order of 10 mi­crons that pro­duce high cur­rent den­si­ties. These ar­rays can be fab­ri­cated in ar­bi­trary shapes such as a tri­an­gle or a dou­ble tri­an­gle, so that they pro­duce an in­her­ently shaped beam. These trans­versely shaped beams can be put through an emit­tance ex­changer to pro­duce a lon­gi­tu­di­nally shaped elec­tron beam dis­tri­b­u­tion for use with high-trans­former ratio wake­field ac­cel­er­a­tors. Sim­u­la­tions are con­ducted with MICHELLE. We de­sign cath­odes and fo­cus­ing sys­tems that pre­serve the beam's shape while trans­port­ing it to the emit­tance ex­changer.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML010  
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THPML012 Simulations and Measurements of the Wakefield Loading Effect in Argonne Wakefield Accelerator Beamline wakefield, linac, acceleration, higher-order-mode 4675
 
  • J. Upadhyay, E.I. Simakov
    LANL, Los Alamos, New Mexico, USA
  • M.E. Conde, Q. Gao, N.R. Neveu, J.G. Power, J.H. Shao, E.E. Wisniewski
    ANL, Argonne, Illinois, USA
  • N.R. Neveu
    IIT, Chicago, Illinois, USA
  
  A beam dri­ven ac­cel­er­a­tion ex­per­i­ment in a pho­tonic band gap (PBG) struc­ture is planned at Ar­gonne wake­fied ac­cel­er­a­tor (AWA) fa­cil­ity at Ar­gonne Na­tional Lab­o­ra­tory. We plan to pass a high charge (drive) beam through a trav­el­ling wave 11.7 GHz PBG struc­ture and gen­er­ate a wake­field. This wake­field will be probed by a low charge (wit­ness) beam to demon­strate wake­field ac­cel­er­a­tion and de­cel­er­a­tion. The drive and wit­ness bunches will be ac­cel­er­ated to above 60 MeV in the main ac­cel­er­a­tor at AWA which has fre­quency of 1.3 GHz. The charges used in this ex­per­i­ment could be as high as 20 nC. To mea­sure the ex­clu­sive ef­fect of PBG the struc­ture on ac­cel­er­a­tion and de­cel­er­a­tion of the wit­ness bunch we have to ex­clude the ef­fect of beam load­ing of the main AWA ac­cel­er­a­tor struc­ture. To un­der­stand the wake­field ef­fect in AWA, we con­ducted an ex­per­i­ment where we passed the high charge (10 nC) beam through the ac­cel­er­a­tor struc­ture which was fol­lowed by a 2 nC wit­ness beam sep­a­rated by 4 wave­length. The en­ergy of wit­ness beam was mea­sured in the pres­ence and ab­sence of the drive beam. The beam load­ing was ob­served and quan­ti­fied. The re­sults of this work will be pre­sented in the con­fer­ence.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML012  
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THPML013 Demonstration of the Wakefield Acceleration in an 11.7 GHz Photonic Band Gap Accelerator Structure wakefield, acceleration, electron, higher-order-mode 4678
 
  • J. Upadhyay, E.I. Simakov
    LANL, Los Alamos, New Mexico, USA
  • M.E. Conde, Q. Gao, N.R. Neveu, J.G. Power, J.H. Shao, E.E. Wisniewski
    ANL, Argonne, Illinois, USA
  
  We plan to con­duct a beam dri­ven ac­cel­er­a­tion ex­per­i­ment in a pho­tonic band gap (PBG) ac­cel­er­a­tor struc­ture op­er­at­ing at 11.7 GHz at Ar­gonne Wake­field Ac­cel­er­a­tor (AWA) fa­cil­ity. For the ex­per­i­ment, the PBG struc­ture will be ex­cited by a high charge (up to 10 nC) elec­tron bunch, and a sec­ond smaller charge wit­ness bunch will be ac­cel­er­ated. Be­cause the PBG struc­ture was fab­ri­cated with elec­tro­form­ing, the AWA beam­line in­cludes a Be win­dow placed be­fore the PBG struc­ture that pro­tects the cath­ode from con­t­a­m­i­na­tion due to pos­si­ble out­gassing from the elec­tro­formed cop­per. The di­am­e­ter of the Be win­dow is 9 mm and the beam tube di­am­e­ter of the PBG struc­ture is 6.4 mm. The size of the high charge elec­tron beam on Be win­dow has to be min­i­mized to min­i­mize scat­ter­ing. The pa­ra­me­ters of the beam­line had to be ad­justed to achieve good prop­a­ga­tion of the beam. An OPAL sim­u­la­tion for the AWA beam­line was per­formed for 1, 5, and 10 nC beams. The beam size was ex­per­i­men­tally mea­sured at dif­fer­ent po­si­tions in the beam­line for dif­fer­ent charges to ver­ify sim­u­la­tions. Fi­nally, the high charge elec­tron beam was passed through the PBG struc­ture and ac­cel­er­a­tion of the wit­ness bunch was mea­sured  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML013  
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THPML014 A Metamaterial Wagon Wheel Structure for Wakefield Acceleration by Reversed Cherenkov Radiation wakefield, simulation, acceleration, electron 4681
 
  • X.Y. Lu, I. Mastovsky, M.A. Shapiro, R.J. Temkin
    MIT/PSFC, Cambridge, Massachusetts, USA
  • M.E. Conde, C.-J. Jing, J.G. Power, J.H. Shao, E.E. Wisniewski
    ANL, Argonne, Illinois, USA
  
  Funding: U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DE-SC0015566 and the U.S. Department of Energy Office of Science under Contract No. DE-AC02-06CH11357
We pre­sent the de­sign and ex­per­i­men­tal op­er­a­tion on an X-band meta­ma­te­r­ial (MTM) wagon wheel struc­ture for wake­field ac­cel­er­a­tion. The struc­ture was de­signed and fab­ri­cated at MIT, and tested at the Ar­gonne Wake­field Ac­cel­er­a­tor (AWA) lab­o­ra­tory at Ar­gonne Na­tional Lab. The MTM wagon wheel struc­ture is an all-metal pe­ri­odic struc­ture at 11.4 GHz. The fun­da­men­tal TM mode has a neg­a­tive group ve­loc­ity, so when an elec­tron beam trav­els through, en­ergy is ex­tracted from the beam by re­versed Cherenkov ra­di­a­tion, which was ver­i­fied in the ex­per­i­ment. Sin­gle bunches up to 45 nC were sent through the struc­ture with a beam aper­ture of 6 mm and gen­er­ated mi­crowave power up to 25 MW in a 2 ns pulse, in agree­ment with both the an­a­lyt­i­cal wake­field the­ory and the nu­mer­i­cal CST sim­u­la­tions. Two bunches with a total charge of 85 nC gen­er­ated 80 MW of mi­crowave power. The struc­ture is scal­able to a power ex­trac­tor of over 1 GW by in­creas­ing the struc­ture length from 8 cm to 22 cm. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML014  
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THPML015 Dielectric Multipactor Discharges at 110 GHz multipactoring, cavity, GUI, vacuum 4684
 
  • S. C. Schaub
    MIT, Cambridge, Massachusetts, USA
  • M.A. Shapiro, R.J. Temkin
    MIT/PSFC, Cambridge, Massachusetts, USA
  
  A 1.5 MW, 110 GHz gy­ro­tron has been used to ex­per­i­men­tally mea­sure the max­i­mum sus­tain­able fields on di­elec­tric ma­te­ri­als in vac­uum. The pur­pose of this work is to eval­u­ate the suit­abil­ity of these ma­te­ri­als for fu­ture ap­pli­ca­tions in high fre­quency lin­ear ac­cel­er­a­tors and high power ter­a­hertz com­po­nents. To our knowl­edge, these are the first mea­sure­ments of mul­ti­pactor phe­nom­ena in the mil­lime­ter wave or ter­a­hertz fre­quency range. Ma­te­ri­als tested in­clude alu­mina, sap­phire, fused quartz, crys­tal quartz, and high re­sis­tiv­ity sil­i­con. Di­elec­tric sam­ples were tested both as win­dows, with elec­tric fields par­al­lel to the sur­face, and sub-wave­length di­elec­tric rod wave­guides, with elec­tric fields per­pen­dic­u­lar to the sur­face. Sur­face elec­tric fields in ex­cess of 52 MV/m were achieved in 3 mi­crosec­ond pulses. Vis­i­ble light emis­sion, ab­sorbed/scat­tered mi­crowave power, and emit­ted elec­trons were mea­sured to char­ac­ter­ize the dis­charges on the di­elec­tric sur­faces. The re­sults of these ex­per­i­ments have been com­pared to the­o­ret­i­cal cal­cu­la­tions of mul­ti­pactor dis­charges, test­ing these the­o­ries at sig­nif­i­cantly higher fre­quen­cies than has been done be­fore.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML015  
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THPML024 Monoenergetic Beam Generated by Laser Accelerator at Peking University laser, proton, quadrupole, acceleration 4702
 
  • K. Zhu, J.E. Chen, Y.X. Geng, C. Li, D.Y. Li, Q. Liao, C. Lin, H.Y. Lu, W.J. Ma, Y.R. Shou, Wu,M.J. Wu, X.H. Xu, X.Q. Yan, J.Q. Yu, Y.Y. Zhao, J.G. Zhu
    PKU, Beijing, People's Republic of China
  
  An ul­tra­high-in­ten­sity laser in­ci­dent on a tar­get sets up a very strong elec­tro­sta­tic field ex­ceed­ing 100 GV/m, it will few or­ders mag­ni­tude shrink down the tra­di­tional radio fre­quency ac­cel­er­a­tors. Whereas, to build a real ac­cel­er­a­tor for rou­tine op­er­a­tion, many sci­en­tific and tech­ni­cal chal­lenges for laser ac­cel­er­a­tion need to over­come be­fore they could be ap­plied to these ap­pli­ca­tions. Re­cently A laser ac­cel­er­a­tor− Com­pact Laser Plasma Ac­cel­er­a­tor (CLAPA) is being built with a beam line to de­liver pro­ton beam with the en­ergy of 1~15MeV, en­ergy spread of ¡À1% and 107-8 pro­tons per pulse. The very high cur­rent pro­ton beam is ac­cel­er­ated in laser ul­tra­thin-foil in­ter­ac­tion and trans­ported by a beam line con­sist­ing of the elec­tric quadru­ple and an­a­lyz­ing mag­nets. It makes sure the good beam qual­i­ties such as en­ergy spread, charge, re­peata­bil­ity and avail­abil­ity of dif­fer­ent en­ergy, which means that for the first laser ac­cel­er­a­tion be­comes a real laser ac­cel­er­a­tor. With the de­vel­op­ment of high-rep rate PW laser tech­nol­ogy, we can now en­vi­sion a com­pact beam ther­a­peu­tic ma­chine of can­cer treat­ment in the near fu­ture soon.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML024  
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THPML031 Collective Acceleration of Laser Plasma in Non-stationary and Non-uniform Magnetic Field plasma, laser, acceleration, target 4716
 
  • A.A. Isaev, C.I. Kozlovskij, E.D. Vovchenko
    MEPhI, Moscow, Russia
  
  This paper pre­sents the new ex­per­i­men­tal re­sults con­cern­ing ac­cel­er­a­tion of deu­terium ions ex­tracted from laser plasma in the rapid-grow­ing nonuni­form mag­netic field in order to ini­ti­ate the nu­clear re­ac­tions D(d, n)3He and Т (d,n)4He. In order to ob­tain plasma a laser that gen­er­ates in Q-switched mode the pulses of in­frared ra­di­a­tion (λ = 1.06 μm) with the en­ergy W ≤ 0.85 J and du­ra­tion of ≈10 ns. In the pre­sent study, the ve­loc­ity of a bunch of a laser plasma at a mag­netic field in­duc­tion rate of 3-108 T/s was ex­per­i­men­tally mea­sured, and an­gu­lar dis­tri­b­u­tions of ac­cel­er­ated par­ti­cle fluxes were mea­sured in the range from 0 to 30 de­grees. The max­i­mum and mean ion ve­loc­i­ties were de­ter­mined by the time-of-flight tech­nique. The pro­posed sys­tem al­lows the gen­er­a­tion of neu­trons, in­clud­ing pos­si­bly ther­monu­clear ones, on coun­ter­flows using two sim­i­lar mag­netic ac­cel­er­a­tors lo­cated coax­i­ally, fac­ing each other. In this case the prob­lem re­lated to degra­da­tion of solid neu­tron-gen­er­at­ing tar­gets is re­solved. There also oc­curs a pos­si­bil­ity of fast ac­cu­mu­lated run­ning time of packed solid tar­gets at using of deuteron-tri­tium laser tar­gets.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML031  
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THPML055 Scaled Studies on Radio Frequency Sources for Megawatt-Class Ionospheric Heaters electron, gun, impedance, cathode 4763
 
  • B.L. Beaudoin, T.M. Antonsen, J.A. Karakkad, A.H. Narayan, G.S. Nusinovich, K.J. Ruisard
    UMD, College Park, Maryland, USA
  • R. Fischer
    Naval Research Laboratory (NRL), Washington, USA
  • S.H. Gold, A. Ting
    NRL, Washington,, USA
  
  Funding: Funding for this project and travel is provided by the Air Force Office of Scientific Research under grant FA95501410019.
The ionos­phere plays a promi­nent role in the per­for­mance of crit­i­cal civil­ian and mil­i­tary com­mu­ni­ca­tion sys­tems. The key in­stru­ment in Ionos­pheric Mod­i­fi­ca­tion (IM) re­search is a pow­er­ful, ground-based, High Fre­quency (HF) source of elec­tro­mag­netic waves known as a heater. With a mo­bile heater, in­ves­ti­ga­tors would be able to con­duct IM re­search at dif­fer­ent lat­i­tudes with­out build­ing a costly per­ma­nent in­stal­la­tion. A new highly ef­fi­cient Megawatt class of Radio Fre­quency sources is re­quired to re­duce the over­all power de­mands on a fully de­ploy­able sys­tem. Such a source has been de­scribed pre­vi­ously*. Re­sults of a scaled ex­per­i­ment, using the elec­tron beam pro­duced by a grid­ded gun to drive an ex­ter­nal lumped el­e­ment cir­cuit for high ef­fi­ciency radio fre­quency gen­er­a­tion is pre­sented. The IOT gun pro­duces an elec­tron beam bunched at the dri­ving fre­quency that is then col­lected by an ex­ter­nal cir­cuit for im­ped­ance match­ing to the load. Re­sults showed that ef­fects such as the in­ter­nal re­sis­tance of the in­duc­tor and de­flec­tion of beam elec­trons by the in­duced RF volt­ages on the beam col­lec­tor are im­por­tant con­sid­er­a­tions to be in­cluded in the de­sign of a prac­ti­cal de­vice.
* B.L. Beaudoin, G.S. Nusinovich, G. Milikh, A. Ting, S. Gold, J.A. Karakkad, A.H. Narayan, D.B. Matthew, D.K. Papadopoulos, T.M. Antonsen Jr., Journal of Elec. Waves and Appl.,31,17,pp.1786, 2017. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML055  
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THPML062 A Beam Based Method to Optimize the SBPM System FEL, electron, quadrupole, site 4780
 
  • J. Chen
    SINAP, Shanghai, People's Republic of China
  • L.W. Lai, Y.B. Leng, T. Wu, R.X. Yuan
    SSRF, Shanghai, People's Republic of China
  
  For the elec­tron ac­cel­er­a­tor, it is hoped that the tra­jec-tory of the beam can pass through the mag­netic cen­ter of the quadru­pole to min­i­mize the or­bital mo­tion caused by the in­sta­bil­ity of the power sup­ply. The rel­a­tive de­vi­a­tion be­tween the mag­netic cen­ter of quadru­pole and the elec-tric cen­ter of ad­ja­cent BPM is mea­sured by elec­tron beam usu­ally in var­i­ous ac­cel­er­a­tor fa­cil­i­ties. But for the stripline BPM (SBPM) sys­tem, in order to achieve the best per­for­mance, the beam tra­jec­tory should also need to pass through the elec­tri­cal cen­ter of the SBPM sys­tem. In this paper, a beam based method to op­ti­mize the SBPM sys­tem was pro­posed, the in­ten­sity of the mag­net power was scanned to change the beam po­si­tion in two-di­men­sion and com­bine the change trend of the sum sig­nal of ad­ja­cent SBPM to find out the rel­a­tive de­vi­a­tion of BPM elec­tric cen­ter and me­chan­i­cal cen­ter. Rel­e­vant beam ex­per­i­ment work on the Shang­hai Soft X-ray free elec­tron laser (SXFEL) and the ben­e­fit of this method will be ad­dressed as well.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML062  
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THPML067 SXFEL Linac BPM System Development and Performance Evaluation FEL, linac, status, electron 4794
 
  • F.Z. Chen, T. Wu
    SSRF, Shanghai, People's Republic of China
  • J. Chen, L.W. Lai, Y.B. Leng, L.Y. Yu, R.X. Yuan
    SINAP, Shanghai, People's Republic of China
  
  Shang­hai Soft X-ray Free Elec­tron Laser (SXFEL) is a test fa­cil­ity to study key tech­nolo­gies and new FEL physics. In order to de­liver high qual­ity elec­tron beams to the un­du­la­tor sec­tion, a high res­o­lu­tion (bet­ter than 10 mi­crons with 200pC beam) Linac beam po­si­tion mon­i­tor sys­tem has been de­vel­oped. The sys­tem con­sists of stripline pickup and cus­tom de­signed DBPM proces­sor. The hard­ware and soft­ware ar­chi­tec­ture will be in­tro­duced in this paper. The on­line per­for­mance eval­u­a­tion re­sults will be pre­sented as well.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML067  
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THPML068 Upgrade of Bunch Phase Monitor at SSRF Storage Ring injection, SRF, storage-ring, pick-up 4797
 
  • Y.M. Zhou, Y.B. Leng, T. Wu, N. Zhang
    SSRF, Shanghai, People's Republic of China
  
  Beam in­sta­bil­ity is a se­ri­ous prob­lem for physics in beam di­ag­no­sis tech­nol­ogy. With re­gard to the eval­u­a­tion of lon­gi­tu­di­nal phase os­cil­la­tions dur­ing the tran­sient in­jec­tion process, bunch-by-bunch phase mea­sure­ment is a use­ful tool for study­ing the be­hav­ior of the re­filled bunches. A new up­graded beam phase mon­i­tor sys­tem with 1.2GHz band­width PXI wave­form dig­i­tizer has been de­vel­oped at Shang­hai syn­chro­tron ra­di­a­tion source (SSRF). Bunch-by-bunch phase in­for­ma­tion, re­trieved from but­ton pickup sig­nals, is cal­cu­lated by the zero-cross­ing de­tec­tion method with the best phase res­o­lu­tion of 0.4ps. The re­filled bunches can be sep­a­rated from the stored ones, and the lon­gi­tu­di­nal off­set of each re­filled bunch has been mea­sured. Sev­eral groups of ex­per­i­ments have been per­formed to ver­ify the re­peata­bil­ity of bunch-by-bunch phase mea­sure­ment, and some re­sults re­gard­ing re­filled bunches will be dis­cussed in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML068  
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THPML070 Point Spread Function Study of Quasi-Monochromatic X-Ray Pinhole Camera at SSRF simulation, photon, SRF, synchrotron 4803
 
  • B. Gao, H.J. Chen
    SINAP, Shanghai, People's Republic of China
  • J. Chen, Y.B. Leng
    SSRF, Shanghai, People's Republic of China
  
  Since 2009 an X-ray pin­hole cam­era that has been used to pre­sent the trans­verse beam size and emit­tance on di­ag­nos­tic beam line of the stor­age ring at SSRF. The real beam size is a func­tion of the image size of the CCD cam­era and point spread func­tion (PSF) of the sys­tem. The per­for­mance of the mea­sure­ment of the trans­verse elec­tron beam size is given by the width of the PSF of X-ray pin­hole cam­era. The con­tri­bu­tions to the PSF width are the PSF of pin­hole it­self due to dif­frac­tion, and the PSF of the screen and cam­era. An X-ray mono­chro­matic sys­tem has been es­tab­lished to mea­sure the PSF ac­cu­rately, and de­crease the vari­a­tion in the beam size be­tween the the­o­ret­i­cal val­ues and the mea­sured ones at SSRF. In this ar­ti­cle, both cal­cu­lated and mea­sured PSF of quasi-mono­chro­matic X-ray pin­hole cam­era will be pre­sented in de­tail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML070  
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THPML091 Design of a High Gradient 60 GHz Dielectric Accelerating Structure acceleration, electromagnetic-fields, electron, simulation 4873
 
  • D.Z. Cao, D. Dan, W. Gai, C.-X. Tang, H. Zha
    TUB, Beijing, People's Republic of China
  
  RF break­down are the main lim­i­ta­tion for the ap­pli­ca­tion of high gra­di­ent struc­tures. Higher fre­quen­cies and shorter pulse length ben­e­fit the de­sign of ac­cel­er­at­ing struc­ture for the break­down thresh­old of sur­face field is Es=f1/2 τ-1/4. Power source which gen­er­ates very short V-band pulse with nearly hun­dred megawatt is now avail­able. The paper pre­sents the analy­sis of a V-band di­elec­tric ac­cel­er­a­tion struc­ture and power source. Fu­ture plan about RF trans­mis­sion and power cou­pling of the whole struc­ture will be dis­cussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML091  
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THPML093 New Fast Kicker Results from the Muon g-2 E-989 Experiment at Fermilab kicker, monitoring, simulation, MMI 4879
 
  • A.P. Schreckenberger
    The University of Texas at Austin, Austin, Texas, USA
  • D. Barak, C.C. Jensen, G.E. Krafczyk, R.L. Madrak, H. Nguyen, H. Pfeffer, M. Popovic, J.C. Stapleton, C. Stoughton
    Fermilab, Batavia, Illinois, USA
  • A.T. Chapelain, A.A. Mikhailichenko, D. L. Rubin
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • N.S. Froemming
    CENPA, Seattle, Washington, USA
  • J.L. Holzbauer
    UMiss, University, Mississippi, USA
  • A.I. Keshavarzi
    The University of Liverpool, Liverpool, United Kingdom
  
  We de­scribe the in­stal­la­tion, com­mis­sion­ing, and char­ac­ter­i­za­tion of the in­jec­tion kicker sys­tem for the E-989 ex­per­i­ment at Fer­mi­lab for a pre­ci­sion mea­sure­ment of the muon anom­alous mag­netic mo­ment. Con­trol and mon­i­tor­ing sys­tems have been im­ple­mented to ac­quire and record the wave­forms of each kicker pulse, and mea­sure­ments of var­i­ous kicker sys­tem ob­serv­ables were recorded in the pres­ence of the 1.45 T g-2 stor­age ring mag­netic field. These mon­i­tor­ing sys­tems are nec­es­sary to un­der­stand the sys­tem­atic con­tri­bu­tion to the mea­sure­ment of the pre­ces­sion fre­quency. We ex­am­ine the de­pen­dence of muon cap­ture to kicker field pre­dic­tions.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML093  
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THPML098 Design of Beam Profile Monitor Used at the Xi'an Proton Application Facility (XiPAF) detector, proton, radiation, synchrotron 4892
 
  • D. Wang, Z.M. Wang
    State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, Shannxi, People's Republic of China
  • W. Chen
    NINT, Xi'an, People's Republic of China
  • P.F. Ma, Y.G. Yang
    TUB, Beijing, People's Republic of China
  • W. Wang
    Tsinghua University, Beijing, People's Republic of China
  
  A pixel ion­iza­tion cham­ber for beam pro­file mon­i­tor (BPrM) is de­signed and man­u­fac­tured by a new tech­nol­ogy .The de­tec­tor will be in­stalled on the beam line just up­stream of the tar­get de­vice of XiPAF. It has many ad­van­tages such as high res­o­lu­tion, high ra­di­a­tion hard­ness and it can work as a real-time mon­i­tor to show the dis­tri­b­u­tion of the de­liv­ered rel­a­tive dose. The physics de­sign and con­struc­tion of the de­tec­tor are de­scribed in this paper, and its per­for­mances are tested of­fline.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML098  
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THPML100 A High Voltage Feedforward Subsystem of Low Level RF System for the High Power RF System high-voltage, LLRF, low-level-rf, controls 4898
 
  • Z.Y. Lin, Y. C. Du, H.Q. Feng, W.-H. Huang, CY. Song, C.-X. Tang, Y.L. Xu, J. Yang
    TUB, Beijing, People's Republic of China
  • G. Huang
    LBNL, Berkeley, California, USA
  
  The Low Level Radio Fre­quency con­trol (LLRF) sys­tem mea­sures the RF sig­nals from the ac­cel­er­a­tor tube, com­pares it with the phase ref­er­ence re­ceived from the tim­ing dis­tri­b­u­tion sys­tem, and pro­vides the drive sig­nal to the high power RF sys­tem to pro­vide syn­chro­nized RF volt­age to the elec­tron beam. Usu­ally, the LLRF sys­tem can achieve a ~50 fs RMS phase jit­ter which is lim­ited by the mi­crowave de­vices. The phase noise arise from the high volt­age vari­a­tion of the high power sys­tem will sig­nif­i­cantly in­crease phase noise from low level RF sig­nal to high power RF. A high volt­age feed for­ward sub­sys­tem is pro­posed to deal with the phase noise caused by the high volt­age jit­ter of the mod­u­la­tor. The demo sys­tem is de­polyed in Thom­son scat­ter­ing X-ray source (TTX).and the pri­mary ex­per­i­ment re­sult anaylse is dis­cussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML100  
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THPML101 A Novel Double Sideband-Based Phase Averaging Line for Phase Reference Distribution System LLRF, laser, FPGA, pick-up 4901
 
  • Z.Y. Lin, Y.-C. Du, W.-H. Huang, Z. Pan, C.-X. Tang, C.-X. Tang, Y.L. Xu, J. Yang
    TUB, Beijing, People's Republic of China
  • G. Huang
    LBNL, Berkeley, California, USA
  
  Coax­ial cable based so­lu­tion is one of the most im­por­tant scheme in Phase Ref­er­ence Dis­tri­b­u­tion Sys­tem. A novel dou­ble side­band-based phase av­er­ag­ing line has been de­vel­oped in Ts­inghua ac­cel­er­a­tor lab. The sender chas­sis gen­er­ates the 2856 MHz sig­nal as the for­ward sig­nal and re­ceives the 2856 MHz sig­nal and the re­flected dou­ble side­band sig­nal from the re­ceiver. The for­ward sig­nal is phase-locked with the ref­er­ence sig­nal, and the for­ward sig­nal and the side­band sig­nal are ad­justed by the FPGA vir­tual delay line. The pre­lim­i­nary ex­per­i­ments re­sult shows the phase sta­bil­ity can achieve about 1% by sig­nal dis­torted by the phase shifter.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML101  
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THPML106 Electron Microscopy Inspired Setup for Single-Shot 4-D Trace Space Reconstruction of Bright Electron Beams emittance, electron, detector, focusing 4909
 
  • J. Giner Navarro, D.B. Cesar, P. Musumeci
    UCLA, Los Angeles, California, USA
  • R.W. Aßmann, B. Marchetti, D. Marx
    DESY, Hamburg, Germany
  
  Funding: This work has been partially supported by the National Science Foundation under Grant No. 1549132 and Department of Energy under award No. DE-SC0009914.
In the de­vel­op­ment of low charge, sin­gle-shot di­ag­nos­tics for high bright­ness elec­tron beams, Trans­mis­sion Elec­tron Mi­croscopy (TEM) grids pre­sent cer­tain ad­van­tages com­pared to pep­per pot masks due to higher beam trans­mis­sion. In this paper, we de­vel­oped a set of cri­te­ria to op­ti­mize the res­o­lu­tion of a point pro­jec­tion image. How­ever, this con­fig­u­ra­tion of the beam with re­spect to the grid and de­tec­tor po­si­tions im­plies the mea­sure­ment of a strongly cor­re­lated phase space which en­tails a large sen­si­tiv­ity to small mea­sure­ment er­rors in re­triev­ing the pro­jected emit­tance. We dis­cuss the pos­si­bil­ity of an al­ter­na­tive scheme by in­sert­ing a mag­netic fo­cus­ing sys­tem in be­tween the grid and the de­tec­tor, sim­i­lar to an elec­tron mi­cro­scope de­sign, to re­con­struct the phase space when the beam is fo­cused on the grid. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML106  
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THPML107 Steering Optimizations for the University of Maryland Electron Ring closed-orbit, dipole, lattice, injection 4913
 
  • L. Dovlatyan, B.L. Beaudoin, R.A. Kishek, K.J. Ruisard
    UMD, College Park, Maryland, USA
  
  Funding: This work is supported by the US Dept. of Energy, Office of High Energy Physics award # DE-SC0010301
The Uni­ver­sity of Mary­land Elec­tron Ring (UMER) has the flex­i­bil­ity to set up al­ter­na­tive lat­tices for dif­fer­ent re­search ex­per­i­ments, in­clud­ing non­lin­ear op­tics stud­ies using oc­tupoles. Each al­ter­na­tive lat­tice re­quires an ac­cept­able steer­ing so­lu­tion for use in ex­per­i­ments. Ex­ist­ing beam-based align­ment tools can take a sig­nif­i­cant amount of time to run and be­come dif­fi­cult to process with a low num­ber of BPMs. The Ro­bust Con­ju­gate Di­rec­tional Search (RCDS) op­ti­mizer* is used to quickly ob­tain steer­ing so­lu­tions for dif­fer­ent lat­tice con­fig­u­ra­tions and has been adopted for beam steer­ing at UMER. Steer­ing mag­nets are op­ti­mized on­line to re­duce scrap­ing, cor­rect equi­lib­rium or­bits, and in­crease beam life­times. This study pre­sents the ap­pli­ca­tion of the op­ti­mizer at UMER.
* X. Huang, J. Corbett, J. Safranek, J. Wu, Nucl. Instr. Meth. A vol. 726, pp. 77-83, 2013. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML107  
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THPML111 Test of the Tune Measurement System Based on BBQ at HLS-II Storage Ring betatron, storage-ring, ion-source, controls 4926
 
  • L.T. Huang, F.L. Gao, P. Lu, B.G. Sun, H.Q. Wang, J.G. Wang, Q. Wang, F.F. Wu, Y.L. Yang, T.Y. Zhou
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  Funding: Supported by the National Science Foundation of China (Grant No. 11705203, 11575181)
The HLS-II stor­age ring is a cru­cial part of Hefei Light Source. Tune is one of the most im­por­tant pa­ra­me­ters of the elec­tron stor­age ring, of which the tune mea­sure­ment sys­tem is an in­te­gral com­po­nent. In this paper, the de­sign of a new tune mea­sure­ment sys­tem based on BBQ (base band tune), is pre­sented. Some ex­per­i­ments are per­formed to test this sys­tem. The new sys­tem is com­pared with the orig­i­nal sys­tem and the TBT (turn-by-turn) method re­spec­tively. The ob­tained re­sults il­lus­trate higher ac­cu­racy and higher sta­bil­ity for the new sys­tem. A new ap­proach of cal­cu­lat­ing the be­ta­tron os­cil­la­tion am­pli­tude is pro­posed, and the be­ta­tron os­cil­la­tion am­pli­tudes in the nor­mal run­ning stage for the HLS-II stor­age ring are es­ti­mated at 95 nm (hor­i­zon­tal) and 60 nm (ver­ti­cal). 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML111  
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THPML120 Development of Coating Technique for Superconducting Multilayered Structure site, cavity, target, acceleration 4954
 
  • R. Ito, T. Nagata
    ULVAC, Inc, Chiba, Japan
  • H. Hayano, T. Kubo, T. Saeki
    KEK, Ibaraki, Japan
  • H. Ito
    Sokendai, Ibaraki, Japan
  • Y. Iwashita, R. Katayama
    Kyoto ICR, Uji, Kyoto, Japan
  • H. Oikawa
    Utsunomiya University, Utsunomiya, Japan
  
  In order to in­crease the max­i­mum ac­cel­er­a­tion gra­di­ent of SRF cav­i­ties, S-I-S (su­per­con­duc­tor-in­su­la­tor-su­per­con­duc­tor) mul­ti­lay­ered struc­ture the­ory has been pro­posed. We fo­cused on NbN which has a higher su­per­con­duct­ing tran­si­tion tem­per­a­ture than Nb. Firstly, we re­searched the op­ti­mal de­po­si­tion con­di­tion for N2 gas re­ac­tive sput­ter­ing of NbN by using in-house in­ter-back type DC mag­netron sput­ter­ing equip­ment. The crit­i­cal con­di­tion for a thin film with strong crys­talline ori­en­ta­tion of NbN was iden­ti­fied. The su­per­con­duct­ing tran­si­tion tem­per­a­ture of the NbN thin film, which were coated under the best con­di­tion, was over 14 K. Sec­ondly, we tried mak­ing S-I-S mul­ti­lay­ered sam­ples that was com­posed of NbN/SiO2/Nb sub­strate. The coat­ing con­di­tion for the NbN layer was de­ter­mined based on the re­search re­sults in a sin­gle layer. The SiO2 layer was de­posited with a film thick­ness of 30 nm that was the­o­ret­i­cally ex­pected to be ef­fec­tive as bar­rier layer. We ap­plied O2 gas re­ac­tive AC mag­netron sput­ter­ing for coat­ing. In this ar­ti­cle, the de­tailed re­sults of the NbN sin­gle layer and mul­ti­layer film de­po­si­tions are pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML120  
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THPML123 The ESR Barrier-Bucket LLRF System - Design and First Results LLRF, cavity, controls, synchrotron 4964
 
  • J. Harzheim, D. Domont-Yankulova, K. Groß, H. Klingbeil
    TEMF, TU Darmstadt, Darmstadt, Germany
  • M. Frey, H. Klingbeil, D.E.M. Lens
    GSI, Darmstadt, Germany
  
  At GSI, Darm­stadt, Ger­many, a Bar­rier-Bucket (BB) RF Sys­tem is cur­rently under de­vel­op­ment for the Ex­per­i­men­tal Stor­age Ring (ESR). The sys­tem con­sists of two broad­band RF cav­i­ties, each dri­ven by a solid state am­pli­fier, with the pur­pose to pro­duce two volt­age pulses per beam rev­o­lu­tion. This will en­able highly so­phis­ti­cated lon­gi­tu­di­nal beam ma­nip­u­la­tions like lon­gi­tu­di­nal cap­ture, com­pres­sion and de­com­pres­sion or stack­ing of the beam. For the LLRF Sys­tem, sev­eral re­quire­ments have to be ful­filled. Be­sides high stan­dards con­cern­ing the pulsed gap sig­nal qual­ity (e.g. ring­ing <2.5%), the sys­tem has to pro­vide the flex­i­bil­ity for adi­a­batic volt­age ramp-up and adi­a­batic pulse shift­ing with high tim­ing ac­cu­racy. A con­nec­tion to the FAIR Cen­tral Con­trol Sys­tem (CCS) is nec­es­sary, as am­pli­tude and phase ramp data will be pro­vided by the CCS. In this con­tri­bu­tion, the struc­ture of the ESR BB LLRF sys­tem is pre­sented to­gether with ex­per­i­men­tal re­sults from the first ver­sion of the sys­tem, which will be in­stalled in the ESR in March 2018.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML123  
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FRXGBD2 Fast Kicker for High Current Beam Manipulation: Experimental Facility kicker, simulation, septum, electron 5019
 
  • V.V. Gambaryan, A.A. Starostenko
    BINP SB RAS, Novosibirsk, Russia
  • A.A. Starostenko
    NSU, Novosibirsk, Russia
  
  The pulsed de­flect­ing mag­net (kicker) pro­ject was worked out in Bud­ker In­sti­tute of Nu­clear Physics. The kicker de­sign pa­ra­me­ters are: im­pul­sive force, 1 mT*m; pulse edge, 5 ns; im­pulse du­ra­tion, 200 ns. The un­con­ven­tional ap­proach is that the plates must be re­placed by a set of cylin­ders. The ob­tained mag­net con­struc­tion en­ables the field ho­mo­gene­ity to be con­trolled by chang­ing cur­rent mag­ni­tudes in cylin­ders. Fur­ther­more, we demon­strated the method of field op­ti­miza­tion. In ad­di­tion, mea­sure­ment tech­nique for the har­monic com­po­nents was con­sid­ered and the pos­si­bil­ity of con­trol har­monic com­po­nents value was demon­strated. The re­sults with elec­tron beam on ac­tual fa­cil­ity was con­sid­ered.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-FRXGBD2  
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FRXGBD4 Observation of Saw-Tooth Effect Orbit in the VEPP-4 M Collider electron, positron, collider, storage-ring 5026
 
  • Leshenok D. Leshenok, E.A. Bekhtenev
    NSU, Novosibirsk, Russia
  • E.A. Bekhtenev, G.V. Karpov, S.A. Nikitin, O.A. Plotnikova
    BINP SB RAS, Novosibirsk, Russia
  
  We study the rel­a­tive po­si­tion of the elec­tron and posi-tron closed or­bits in the VEPP-4M sin­gle stor­age ring col­lider in ex­per­i­ments on orbit pre­ci­sion mon­i­tor­ing. A dif­fer­ence in the or­bits can af­fect the ac­cu­racy of sev­eral fun­da­men­tal ex­per­i­ments, e.g. pre­cise com­par­i­son of the elec­tron and positron spin fre­quen­cies (the CPT in­vari-ance test) [1]. In this case, the spin pre­ces­sion fre­quen­cies of par­ti­cles should be com­pared within at least 5·10-9. The dis­tinc­tion of fre­quen­cies de­pends on the fea­tures of the ra­dial or­bits. Ide­ally, the dif­fer­ence in the elec­tron and positron or­bits is set only by dis­trib­uted ra­di­a­tion losses of par­ti­cle en­ergy. The cor­re­spond­ing con­tri­bu­tion to the total orbit dis­tor­tions is called the Saw-Tooth ef­fect orbit. An­other ex­am­ple of pos­si­ble pre­ci­sion ex­per­i­ment at VEPP-4M is search for the light speed anisotropy (LSA). In this case, it is nec­es­sary to en­sure a sta­bil­ity of the dif­fer­ence in the ra­dial or­bits of elec­trons and positrons at a level of 1μm.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-FRXGBD4  
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FRXGBE2 Muon Beam Dynamics and Spin Dynamics in the g-2 Storage Ring quadrupole, storage-ring, injection, positron 5029
 
  • D. L. Rubin, A.T. Chapelain
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • S. Charity, J. Price
    The University of Liverpool, Liverpool, United Kingdom
  • J.D. Crnkovic, W. Morse, V. Tishchenko
    BNL, Upton, Long Island, New York, USA
  • F.E. Gray
    Regis University, Denver, USA
  • J. E. Mott
    BUphy, Boston, Massachusetts, USA
  • W. Wu
    UMiss, University, Mississippi, USA
  
  Funding: This work was supported in part by the U.S. Department of Energy DOE HEP DE-SC0008037
The goal of the new g-2 ex­per­i­ment at fer­mi­lab is a mea­sure­ment of the anom­alous mag­netic mo­ment of the muon, with un­cer­tainty of less than 140 ppb. The ex­per­i­men­tal method is to store a beam of po­lar­ized muons in a stor­age ring with pure ver­ti­cal di­pole field and elec­tro­sta­tic fo­cus­ing, and to mea­sure the pre­ces­sion fre­quency. Con­trol of the sys­tem­at­ics de­pends on un­prece­dented knowl­edge of the de­tails of the phase space of the muon dis­tri­b­u­tion. That knowl­edge is de­rived from di­rect mea­sure­ments with scin­til­lat­ing fiber de­tec­tors that are in­serted into the muon beam for di­ag­nos­tic mea­sure­ments, trace­back straw tube track­ing cham­bers, as well as the calorime­ters that mea­sure en­ergy, time and po­si­tion of the decay positrons. The in­ter­pre­ta­tion of the mea­sure­ments de­pends on a de­tailed model of the stor­age ring guide field. This in­vited talk pre­sents re­sults of stud­ies of the dis­tri­b­u­tion from the com­mis­sion­ing run of the ex­per­i­ment. 		 
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-FRXGBE2  
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FRXGBE3 First Demonstration of Ionization Cooling in MICE emittance, detector, electron, solenoid 5035
 
  • T.A. Mohayai
    IIT, Chicago, Illinois, USA
  
  The Muon Ion­iza­tion Cool­ing Ex­per­i­ment (MICE) at Ruther­ford Ap­ple­ton Lab­o­ra­tory has stud­ied ion­iza­tion cool­ing of muons. Sev­eral mil­lion in­di­vid­ual muon tracks have been recorded pass­ing through a se­ries of fo­cus­ing mag­nets and a liq­uid hy­dro­gen or lithium hy­dride ab­sorber in a va­ri­ety of mag­netic con­fig­u­ra­tions. Iden­ti­fi­ca­tion and mea­sure­ment of muon tracks up­stream and down­stream of the ab­sorber are used to study the evo­lu­tion of the 4D (trans­verse) emit­tance. This paper pre­sents and dis­cusses these re­sults.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-FRXGBE3  
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FRXGBF1 Re-Acceleration of Ultra Cold Muon in J-PARC Muon Facility linac, rfq, acceleration, emittance 5041
 
  • Y. Kondo, K. Hasegawa, T. Morishita
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • S. Bae, H. Choi, S. Choi, B. Kim, H.S. Ko
    SNU, Seoul, Republic of Korea
  • Y. Fukao, K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, M. Otani, K. Shimomura, T. Yamazaki, M. Yoshida
    KEK, Tsukuba, Japan
  • N. Hayashizaki
    RLNR, Tokyo, Japan
  • T. Iijima, Y. Sue
    Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
  • H. Iinuma, Y. Nakazawa
    Ibaraki University, Ibaraki, Japan
  • K. Ishida
    RIKEN Nishina Center, Wako, Japan
  • Y. Iwashita
    Kyoto ICR, Uji, Kyoto, Japan
  • Y. Iwata
    NIRS, Chiba-shi, Japan
  • R. Kitamura
    University of Tokyo, Tokyo, Japan
  • S. Li
    The University of Tokyo, Graduate School of Science, Tokyo, Japan
  • G.P. Razuvaev
    Budker INP & NSU, Novosibirsk, Russia
  • N. Saito
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  
  Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP16H03987, and JP16J07784.
J-PARC is de­vel­op­ing the reac­cel­er­a­tion sys­tem of the ultra slow (30 meV) muon (USM) ob­tained by two-pho­ton laser res­o­nant ion­iza­tion of muo­nium atoms. The muon beam thus ob­tained has low emit­tance, meet­ing the re­quire­ment for the g-2/EDM ex­per­i­ment. J-PARC E34 ex­per­i­ment aims to mea­sure the muon anom­alous mag­netic mo­ment (g-2) with a pre­ci­sion of 0.1 ppm and search for EDM with a sen­si­tiv­ity to 10-21 e cm. The USM's are ac­cel­er­ated to 212 MeV by using a muon ded­i­cated linac to be a ultra cold muon beam. The muon LINAC con­sists of an RFQ, a in­ter-dig­i­tal H-mode DTL, disk and washer cou­pled cell struc­tures, and disk loaded struc­tures. The ul­tra-cold muons will have an ex­tremely small trans­verse mo­men­tum spread of 0.1% with a nor­mal­ized trans­verse emit­tance of around 1.5 pi mm-mrad. Proof of the slow muon ac­cel­er­a­tion scheme is an es­sen­tial step to re­al­ize the world first muon linac. In Oc­to­ber 2017, we have suc­ceeded to ac­cel­er­ate slow neg­a­tive muo­ni­ums gen­er­ated using a sim­pler muo­nium source to 89 keV. In this talk, pre­sent de­sign of the muon linac and the re­sult of the world first muon ac­cel­er­a­tion ex­per­i­ment are re­ported. 		 
slides icon Slides FRXGBF1 [8.373 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-FRXGBF1  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)