Keyword: acceleration
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MOZGBE1 Development of Gas Stripper at RIBF plasma, target, electron, heavy-ion 41
 
  • H. Imao
    RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama, Japan
  
  Charge strip­pers are al­most in­evitable for ac­cel­er­a­tions in heavy-ion ac­cel­er­a­tor com­plex. The fixed solid strip-pers in­clud­ing car­bon-foil strip­pers are dif­fi­cult to be used in on-go­ing or up­com­ing new-gen­er­a­tion in-flight RI beam fa­cil­i­ties, e.g., RIBF (RIKEN, Japan), FAIR (GSI, Ger­many), FRIB (NSCL/MSU, US), HIAF (IMP, China) and RAON (RISP, Korea). The He gas strip­per de­vel­oped at RIBF is the first suc­cess­ful strip­per sig­nif­i­cantly be-yond the ap­plic­a­ble limit of the fixed car­bon-foil strip-pers. We dis­cuss the de­vel­op­ment of the gas strip­pers at RIBF and overview the re­lated new-gen­er­a­tion strip­pers being de­vel­oped in the world.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOZGBE1  
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MOPMF013 eRHIC EIC: Plans for Rapid Acceleration of Polarized Electron Bunch at Cornell Synchrotron polarization, electron, synchrotron, resonance 108
 
  • F. Méot, E.C. Aschenauer, H. Huang, C. Montag, V. Ptitsyn, V.H. Ranjbar, E. Wang, Z. Zhao
    BNL, Upton, Long Island, New York, USA
  • I.V. Bazarov, D. L. Rubin
    Cornell University, Ithaca, New York, USA
  • L. Cultrera, G.H. Hoffstaetter, K.W. Smolenski, R.M. Talman
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • D. Gaskell, O. Glamazdin, J.M. Grames
    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.
An op­tion as an in­jec­tor into the po­lar­ized-elec­tron stor­age ring of eRHIC EIC is a rapid-cy­cling syn­chro­tron (RCS). Cor­nell's 10 GeV RCS in­jec­tor to CESR pre­sents a good op­por­tu­nity for ded­i­cated po­lar­ized bunch rapid-ac­cel­er­a­tion ex­per­i­ments, it can also serve as a test bed for source and po­larime­try de­vel­op­ments in the frame of the EIC R&D, as po­lar­ized bunch ex­per­i­ments re­quire dis­pos­ing of a po­lar­ized elec­tron source, and of ded­i­cated po­larime­try in the linac re­gion and in the RCS proper. This is as well an op­por­tu­nity for a pluri-dis­ci­pli­nary col­lab­o­ra­tion be­tween Lab­o­ra­to­ries. This paper is an in­tro­duc­tion to the topic, and to on-go­ing ac­tiv­i­ties to­wards that EIC R&D pro­ject. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF013  
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MOPMF072 On the Feasibility of a Pulsed 14 TeV C.M.E. Muon Collider in the LHC Tunnel collider, luminosity, proton, SRF 296
 
  • V.D. Shiltsev, D.V. Neuffer
    Fermilab, Batavia, Illinois, USA
  
  We will con­sider tech­ni­cal fea­si­bil­ity, key ma­chine pa­ra­me­ters and major chal­lenges of the re­cently pro­posed 14 TeV c.m.e. muon-muon col­lider in the LHC tun­nel.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF072  
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MOPMF076 Energy Spread Compensation in Arbitrary Format Multi-Bunch Acceleration With Standing Wave and Traveling Wave Accelerators beam-loading, positron, cavity, linac 307
 
  • M. Kuriki
    HU/AdSM, Higashi-Hiroshima, Japan
  
  In the E-dri­ven ILC (In­ter­na­tional Lin­ear Col­lider) positron source, the beam is gen­er­ated and ac­cel­er­ated in a multi-bunch for­mat with mini-trains. The macro-pulse con­tains 2 to 8 mini-trains with sev­eral train gaps, be­cause the pulse for­mat is a copy of a part of the bunch stor­age pat­tern in DR (Damp­ing Ring). This pulse for­mat causes a vari­a­tion of the ac­cel­er­a­tor field in the pulse due to the tran­sient beam load­ing and an in­ten­sity fluc­tu­a­tion of cap­tured positron. In this ar­ti­cle, we dis­cuss the com­pen­sa­tion of the en­ergy spread of such beam in stand­ing wave and trav­el­ing wave ac­cel­er­a­tors. For stand­ing wave ac­cel­er­a­tor, it can be com­pen­sated by switch­ing input RF at ap­pro­pri­ate tim­ings. For trav­el­ing wave ac­cel­er­a­tor, it can be com­pen­sated by am­pli­tude mod­u­la­tion of the input RF.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF076  
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MOPMF077 A Design Study of the Electron-driven ILC Positron Source Including Beam Loading Effect positron, beam-loading, cavity, booster 311
 
  • H. Nagoshi, M. Kuriki
    HU/AdSM, Higashi-Hiroshima, Japan
  • S. Kashiwagi
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
  • K. Negishi
    Iwate University, Morioka, Iwate, Japan
  • T. Omori, M. Satoh, Y. Seimiya, J. Urakawa
    KEK, Ibaraki, Japan
  • Y. Sumitomo
    LEBRA, Funabashi, Japan
  • T. Takahashi
    Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
  
  The In­ter­na­tional Lin­ear Col­lider (ILC) is a next-gen­er­a­tion ac­cel­er­a­tor for high-en­ergy physics to study the Higgs and top sec­tor in the Stan­dard Model, and new physics such as su­per­sym­me­try and dark mat­ter. ILC positron source based on Elec­tron-dri­ven method has been pro­posed as a re­li­able tech­ni­cal backup. In this ar­ti­cle, we re­port the de­sign study of the positron source based on the off-the-shelf RF com­po­nents. The positron is gen­er­ated and ac­cel­er­ated in a multi-bunch for­mat. To com­pen­sate the en­ergy vari­a­tion by the tran­sient beam load­ing ef­fect, we em­ploy AM (Am­pli­tude Mod­u­la­tion) tech­nique and the re­sults were 16.60 ± 0.14 MV (peak-to-peak) for L-band 2m cav­ity dri­ven by 22.5 MW power and 25.76 ± 0.19 MV (peak-to-peak) for S-band 2m ac-cel­er­a­tor dri­ven by 36 MW power with 0.78 A beam load-ing.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF077  
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MOPML011 Liquid Cluster Ion Beam Processing of Transition Metal Films vacuum, radiation, target, experiment 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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MOPML025 Slow Extraction Optimization at the MedAustron Ion Therapy Center: Implementation of Front End Acceleration and RF Knock Out extraction, proton, synchrotron, kicker 453
 
  • A. De Franco, L. Adler, F. Farinon, N. Gambino, G. Guidoboni, G. Kowarik, M. Kronberger, C. Kurfürst, S. Myalski, S. Nowak, M.T.F. Pivi, C. Schmitzer, I. Strašík, P. Urschütz, A. Wastl
    EBG MedAustron, Wr. Neustadt, Austria
  • L.C. Penescu
    Abstract Landscapes, Montpellier, France
  
  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 675265.
MedAus­tron is a syn­chro­tron-based ion ther­apy cen­ter al­low­ing tu­mour treat­ment with pro­tons and other light ion species, in par­tic­u­lar C6+. Com­mis­sion­ing of all fixed lines, two hor­i­zon­tal and one ver­ti­cal, has been com­pleted for pro­tons and in par­al­lel to the com­mis­sion­ing of a gantry and C6+, a fa­cil­ity up­grade study is pro­gress­ing. The up­grade study en­com­passes the op­ti­miza­tion of the slow ex­trac­tion mech­a­nism by em­ploy­ing the RF empty bucket chan­nel­ing and RF Knock Out tech­niques. The for­mer is a front end ac­cel­er­a­tion tech­nique that sup­press spill rip­ples, fun­da­men­tal to safely op­er­ate the ma­chine at the high­est in­ten­si­ties. The lat­ter is an al­ter­na­tive ex­trac­tion tech­nique which opens up in­ter­est­ing pos­si­bil­i­ties for fast beam en­ergy and in­ten­sity mod­u­la­tions. In this work, we quan­tify spill smoothen­ing ef­fect achieved with the first and re­port the re­sults of a fea­si­bil­ity study of the sec­ond using a Schot­tky mon­i­tor as a trans­verse kicker. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML025  
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MOPML034 Development Status of Superconducting RF Transmission Electron Microscope cavity, LLRF, gun, SRF 481
 
  • N. Higashi, A. Enomoto, Y. Funahashi, T. Furuya, X.J. Jin, Y. Kamiya, S. Michizono, F. Qiu, M. Yamamoto
    KEK, Ibaraki, Japan
  • S. Yamashita
    University of Tokyo, Tokyo, Japan
  
  Now we are de­vel­op­ing a new type of trans­mis­sion elec­tron mi­cro­scope (TEM) em­ploy­ing the ac­cel­er­a­tor tech­nolo­gies. In place of a DC ther­mal gun gen­er­ally used in con­ven­tional TEMs, we apply a pho­to­cath­ode gun and a spe­cial-shaped su­per­con­duct­ing cav­ity, named two-mode cav­ity. The two-mode cav­ity has two res­o­nant modes of TM010 (1.3 GHz) and TM020 (2.6 GHz). To su­per­im­pose these, we can sup­press the in­crease of the en­ergy spread, which is needed for the high-spa­tial-res­o­lu­tion TEMs. We have al­ready de­vel­oped some pro­to­types of the pho­to­cath­ode gun and two-mode cav­ity, and now in the mid­dle of the per­for­mance tests. In this pre­sen­ta­tion, we will show the lat­est sta­tus of the de­vel­op­ment.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML034  
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TUXGBE2 Study of Ultra-High Gradient Acceleration in Carbon Nanotube Arrays plasma, electron, wakefield, experiment 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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TUXGBE4 Beam Quality Limitations of Plasma-Based Accelerators plasma, electron, laser, injection 607
 
  • A. Ferran Pousa, R.W. Aßmann
    DESY, Hamburg, Germany
  • A. Martinez de la Ossa
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  
  Plasma-based ac­cel­er­a­tors are a promis­ing novel tech­nol­ogy that could sig­nif­i­cantly re­duce the size and cost of fu­ture ac­cel­er­a­tor fa­cil­i­ties. How­ever, the typ­i­cal qual­ity and sta­bil­ity of the pro­duced beams is still in­fe­rior to the re­quire­ments of Free Elec­tron Lasers (FELs) and other ap­pli­ca­tions. We pre­sent here our re­cent work in un­der­stand­ing the lim­i­ta­tions of this type of ac­cel­er­a­tors, par­tic­u­larly on the en­ergy spread and bunch length, and pos­si­ble mit­i­gat­ing mea­sures for fu­ture ap­pli­ca­tions, like the plasma-based FEL in the Eu­PRAXIA de­sign study.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUXGBE4  
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TUXGBF4 ORBIT Simulation, Measurement and Mitigation of Transverse Beam Instability in the Presence of Strong Space Charge in the 3-GeV RCS of J-PARC simulation, impedance, injection, space-charge 620
 
  • P.K. Saha, H. Harada, N. Hayashi, H. Hotchi, Y. Shobuda, F. Tamura
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  
  The trans­verse im­ped­ance of eight ex­trac­tion pulse kicker mag­nets (KM) is ex­tremely strong source of trans­verse beam in­sta­bil­ity in the 3-GeV RCS (Rapid Cy­cling Syn­chro­tron) at J-PARC. To re­al­ize the de­signed 1 MW beam power, col­lec­tive beam dy­nam­ics with in­clud­ing the space charge ef­fect for the cou­pled bunch in­sta­bil­i­ties ex­cited by the KM im­ped­ance and as­so­ci­ated mea­sures were stud­ied by in­cor­po­rat­ing all re­al­is­tic time-de­pen­dent ma­chine pa­ra­me­ters in the ORBIT 3-D par­ti­cle track­ing code. The sim­u­la­tion re­sults were all re­pro­duced by mea­sure­ments and, as a con­se­quence, an ac­cel­er­a­tion of 1 MW beam power has been suc­cess­fully demon­strated. In order to main­tain vari­a­tion of the RCS pa­ra­me­ters re­quired for multi-user op­er­a­tion, re­al­is­tic mea­sures for beam in­sta­bil­ity mit­i­ga­tion were pro­posed and also been suc­cess­fully im­ple­mented in re­al­ity. To fur­ther in­crease the RCS beam power, beam sta­bil­ity is­sues and pos­si­ble mea­sures be­yond 1 MW beam power are also con­sid­ered.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUXGBF4  
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TUYGBE3 Recent progress of short pulse dielectric two-beam acceleration linear-collider, collider, experiment, 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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TUYGBF3 An EBIS-Based Low-Energy Accelerator for Fine-Focussed Ion Beams ion-source, electron, target, emittance 647
 
  • M. Schmidt, P. Laux, G.H. Zschornack
    DREEBIT, Großröhrsdorf, Germany
  
  Tech­nolo­gies based on fo­cused ion beams have be­come in­dis­pens­able for re­search in­sti­tu­tions as well as com­mer­cial lab­o­ra­to­ries and high-tech pro­duc­tion fa­cil­i­ties (mi­cro- and nan­otech­nol­ogy, semi­con­duc­tor tech­nol­ogy). We re­port on a com­pact setup com­bin­ing an Elec­tron Beam Ion Source (EBIS), a Wien fil­ter for ion species sep­a­ra­tion, and a fine fo­cus­ing ion ac­cel­er­a­tion col­umn ca­pa­ble of pro­duc­ing ion beams with beam di­am­e­ters in the mi­crom­e­ter range at ion beam en­er­gies up to the MeV range. Al­most all el­e­ments of the pe­ri­odic sys­tem can be in­jected into the EBIS to pro­duce a broad spec­trum of ion charge states with only one ion source. The beam en­ergy of a se­lected ion species can eas­ily be var­ied by chang­ing the elec­tric po­ten­tial of the EBIS drift tube in which the ions are gen­er­ated, re­sult­ing in dif­fer­ent im­plan­ta­tion depths in var­i­ous solids. We pre­sent stud­ies on beam di­am­e­ter and emit­tance, avail­able charge states, and SEM imag­ing as ap­pli­ca­tion.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUYGBF3  
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TUPAF010 Empty Sweeping Bucket for Slow Extraction extraction, resonance, hadrontherapy, synchrotron 676
 
  • L. Falbo, E. Bressi, C. Priano
    CNAO Foundation, Milan, Italy
  
  The ex­trac­tion process from a syn­chro­tron is one of the most im­por­tant as­pects of an ac­cel­er­a­tor de­voted to clin­i­cal pur­poses, like the hadron­ther­apy in which hadron beams are used to treat tu­mors. In­deed the qual­ity of the dose de­liv­ered to the pa­tient, in terms of dose uni­for­mity and pre­ci­sion in the beam char­ac­ter­is­tics, is de­fined by the way in which the beam is ex­tracted. The qual­ity of the ex­tracted beam (the so called spill) is strongly af­fected by the sta­bil­ity of the power sup­plies of the syn­chro­tron mag­nets whose field sta­bil­ity cre­ates a rip­ple in the in­ten­sity of the ex­tracted beam it­self. When it is not pos­si­ble to im­prove the power sup­ply sta­bil­ity, it is needed to apply some ad­di­tional tech­niques in order to cure the spill rip­ple. At CNAO, the ital­ian hadron­ther­apy fa­cil­ity, it has been thought to im­prove the Empty Bucket Chan­nelling tech­nique by using an en­ergy-mov­ing bucket in­stead of a sta­tion­ary bucket. The paper shows the im­ple­men­ta­tion, the ad­van­tages and the ef­fi­cacy of this RF gym­nas­tic, named 'Empty Sweep­ing Bucket'.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF010  
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TUPAF087 A Two-Stage Splitring-RFQ for High Current Ion Beams at Low Frequencies rfq, simulation, impedance, resonance 941
 
  • M. Baschke, H. Podlech, A. Schempp
    IAP, Frankfurt am Main, Germany
  
  Funding: HIC for FAIR, BMBF Contr. No. 05P15RFRBA
For sev­eral ac­cel­er­a­tor pro­jects RFQs are the first stage of ac­cel­er­a­tion. To reach high in­ten­si­ties a new Splitring-RFQ is in­ves­ti­gated. Not only a high cur­rent and high beam qual­ity/bril­liance should be achieved, also a good tun­ing flex­i­bil­ity and com­fort for main­te­nance are part of the study. The RFQ will con­sist of two stages with 27 MHz and 54 MHz to ac­cel­er­ate ions with an A/q of 60 up to en­er­gies of 200 keV/u. RF sim­u­la­tions with CST MWS have been per­formed to ob­tain the qual­ity fac­tor, shunt im­ped­ance and volt­age dis­tri­b­u­tion as well as tun­ing pos­si­bil­i­ties. The re­sults and the sta­tus of the pro­ject will be pre­sented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF087  
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TUPAK004 Superconducting CH-Cavity Heavy Ion Beam Testing at GSI cavity, linac, heavy-ion, emittance 962
 
  • W.A. Barth, M. Heilmann, A. Rubin, A. Schnase, S. Yaramyshev
    GSI, Darmstadt, Germany
  • K. Aulenbacher
    IKP, Mainz, Germany
  • K. Aulenbacher, F.D. Dziuba, V. Gettmann, T. Kürzeder, M. Miski-Oglu
    HIM, Mainz, Germany
  • M. Basten, M. Busch, H. Podlech, M. Schwarz
    IAP, Frankfurt am Main, Germany
  
  Re­cently the first sec­tion of a stand­alone su­per­con­duct­ing (sc) con­tin­u­ous wave (cw) heavy ion Linac as a demon­stra­tion of the ca­pa­bil­ity of 217 MHz multi gap Cross­bar H-mode struc­tures (CH) has been com­mis­sioned and ex­ten­sively tested with beam from the GSI- High Charge State In­jec­tor. The demon­stra­tor set up reached ac­cel­er­a­tion of heavy ions up to the de­sign beam en­ergy and be­yond. The re­quired ac­cel­er­a­tion gain was achieved with heavy ion beams even above the de­sign mass to charge ratio at high beam in­ten­sity and full beam trans­mis­sion. This con­tri­bu­tion pre­sents sys­tem­atic beam mea­sure­ments with vary­ing RF-am­pli­tudes and phases of the CH-cav­ity, as well as ver­sa­tile phase space mea­sure­ments for heavy ion beams with dif­fer­ent mass to charge ratio. The world­wide first and suc­cess­ful beam test with a su­per­con­duct­ing multi gap CH-cav­ity is a mile­stone of the R&D work of Helmholtz In­sti­tute Mainz (HIM) and GSI in col­lab­o­ra­tion with Goethe Uni­ver­sity Frank­furt (GUF) in prepa­ra­tion of the sc cw heavy ion Linac pro­ject and other cw-ion beam ap­pli­ca­tions.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAK004  
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TUPAK012 Conceptual Design of a Single-Ended MA Cavity for J-PARC RCS Upgrade cavity, operation, vacuum, power-supply 987
 
  • M. Yamamoto, M. Nomura, T. Shimada, F. Tamura
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • M. Furusawa, K. Hara, K. Hasegawa, C. Ohmori, Y. Sugiyama, M. Yoshii
    KEK, Tokai, Ibaraki, Japan
  
  The J-PARC RCS em­ployes Mag­netic Alloy (MA) loaded cav­i­ties and rf power is fed by vac­uum tubes in push-pull op­er­a­tion. The multi-har­monic rf dri­ving and the multi-har­monic beam load­ing com­pen­sa­tion are re­al­ized due to the broad­band char­ac­ter­is­tics of the MA. How­ever, the push-pull op­er­a­tion has dis­ad­van­tages in the multi-har­mon­ics. An un­bal­ance of the anode volt­age swing re­mark­ably ap­pears at very high in­ten­sity beam ac­cel­er­a­tion. In order to avoid the un­bal­ance, a sin­gle-ended MA cav­ity is con­sid­ered for the RCS beam power up­grade be­cause no un­bal­ance arises in­trin­si­cally. We will de­scribe the con­cep­tual de­sign of the sin­gle-end MA cav­ity for the RCS up­grade.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAK012  
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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 quadrupole, diagnostics, experiment, 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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TUPAL009 Studying a Prototype of Dual-beam Drift Tube Linac DTL, cavity, rfq, simulation 1020
 
  • T. He, L. Lu, W. Ma, L.P. Sun, C.C. Xing, X.B. Xu, L. Yang
    IMP/CAS, Lanzhou, People's Republic of China
  
  For gen­er­at­ing high-in­ten­sity ion beams from lin­ear ac-cel­er­a­tors, a multi-beam ac­cel­er­a­tion method which in-volves mul­ti­ple ac­cel­er­at­ing beams to sup­press the defo-cus­ing force from space charge ef­fects, then in­te­grat­ing these beams by a beam fun­nel­ing sys­tem, has been pro-posed. An In­ter-dig­i­tal H-mode (IH) two-beam type radio fre­quency quadru­pole (RFQ) with ac­cel­er­at­ing 108mA (54mA/chan­nel×2) car­bon ion from 5 to 60 keV/ u and an IH four-beam RFQ with ac­cel­er­at­ing 160.8mA (40.2mA/chan­nel×4) car­bon ion from 3.6 to 41.6 keV/u had been suc­cess­fully de­signed for low en­ergy heavy ion ac­cel­er­a­tion [1]. In order to demon­strate that an IH dual-beam drift tube linac (DB-DTL) is suit­able for high-in­ten­sity heavy ion beam ac­cel­er­a­tion in mid­dle en­ergy re­gion, we has been de­vel­op­ing a DB-DTL pro­to­type by using three di­men­sional elec­tro­mag­netic CST Mi­croWave Stu­dio (MWS) and using par­ti­cles track­ing Pi Mode Linac Orbit Cal­cu­la­tion (PiM­LOC) [2-3]. Ac­cord­ing to the sim­u­la­tion re­sults, the beam dy­nam­ics de­sign and elec-tro­mag­netic de­sign will be pre­sented in this paper.
* Shota. Iketa et al., Nucl. Instr. and Meth. in Phys. Res. B.239-243 (2017). 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL009  
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TUPAL015 Progress in the Realization and Commissioning of the Exotic Beam Facility SPES at INFN-LNL rfq, cyclotron, target, proton 1035
 
  • G. Bisoffi, A. Andrighetto, P. Antonini, L. Bellan, D. Benini, J. Bermudez, D. Bortolato, M. Calderolla, M. Comunian, S. Corradetti, A. Facco, E. Fagotti, P. Favaron, A. Galatà, F. Galtarossa, M.G. Giacchini, F. Gramegna, A. Lombardi, M. Maggiore, M. Manzolaro, D. Marcato, T. Marchi, P. Mastinu, P. Modanese, M.F. Moisio, A. Monetti, M. Montis, A. Palmieri, S. Pavinato, D. Pedretti, A. Pisent, M. Poggi, G.P. Prete, C. R. Roncolato, M. Rossignoli, L. Sarchiapone, D. Scarpa, D. Zafiropoulos, L. de Ruvo
    INFN/LNL, Legnaro (PD), Italy
  • V. Andreev
    ITEP, Moscow, Russia
  • M.A. Bellato
    INFN- Sez. di Padova, Padova, Italy
  • A.J. Mendez
    ORNL, Oak Ridge, Tennessee, USA
  
  SPES (Se­lec­tive Pro­duc­tion of Ex­otic Species) is an ISOL type fa­cil­ity for pro­duc­tion and post-ac­cel­er­a­tion of ex­otic nu­clei for fore­front re­search in nu­clear physics. Ra­dioac­tive (RA) species (A=80/160) will be pro­duced by fis­sions in­duced by a pro­ton beam im­ping­ing on an UCx tar­get: the pro­ton beam will be de­liv­ered by a com-mer­cial cy­clotron with a 40 MeV max­i­mum en­ergy and a 0.25 mA max­i­mum cur­rent. The RA species, ex­tracted from the Tar­get-Ion-Source sys­tem as a 1+ beam , will be cooled in a RFQ (ra­diofre­quency quadru­pole) beam cool-er (RFQ-BC) and pu­ri­fied from the iso­bars con­t­a­m­i­nants through a High Res­o­lu­tion Mass Sep­a­ra­tor (HRMS). Post-ac­cel­er­a­tion will be per­formed via an ECR-based charge breeder, de­liv­er­ing the ob­tained q+ RA beam to a being built CW RFQ and to the being up­graded su­per­con­duct­ing (sc) linac ALPI (up to 10 MeV/A for a mass-to-charge ratio A/q=7).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL015  
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TUPAL027 Design of Multi-MW Rapid Cycling Synchrotron for Accelerator Driven Transmutation System lattice, extraction, proton, synchrotron 1057
 
  • Y. Fuwa
    Kyoto ICR, Uji, Kyoto, Japan
  • N. Amemiya
    Kyoto University, Kyoto, Japan
  • Y. Ishi, Y. Kuriyama, T. Uesugi
    Kyoto University, Research Reactor Institute, Osaka, Japan
  
  For the prac­ti­cal ap­pli­ca­tion of Ac­cel­er­a­tor Dri­ven Sys­tem (ADS) that re­duces the harm­ful­ness of ra­dioac­tive waste by trans­mu­ta­tion, we are study­ing the de­vel­op­ment of a com­pact ac­cel­er­a­tor using a syn­chro­tron as an ac­cel­er­a­tor ca­pa­ble of sup­ply­ing a sta­ble pro­ton beam to a nu­clear re­ac­tor. In this plan, we aim to re­al­ize down-siz­ing and high re­li­a­bil­ity by adopt­ing an al­ter­nat­ing high tem­per­a­ture su­per­con­duct­ing mag­net and a high rep­e­ti­tion syn­chro­tron ap­ply­ing res­o­nant beam ex­trac­tion. In this pre­sen­ta­tion we re­port the basic de­sign of the op­ti­cal sys­tem and beam ac­cel­er­a­tion se­quence of this syn­chro­tron.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL027  
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TUPAL029 Harmonictron cavity, proton, operation, synchrotron 1063
 
  • Y. Mori
    Kyoto University, Research Reactor Institute, Osaka, Japan
  • H. Arima, N. Ikeda, Y. Yonemura
    Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka, Japan
  • Y. Waga
    Kyushu University, Hakozaki, Japan
  
  The pos­si­bil­ity of high in­ten­sity hadron/lep­ton ac­cel­er­a­tor based on a ver­ti­cal scal­ing FFAG with har­monic num­ber jump ac­cel­er­a­tion, named "Har­mon­ic­tron", has been pro­posed. The pre­sen­ta­tion gives a de­sign ex­am­ple of the Har­mon­ic­tron for ac­cel­er­at­ing pro­tons from 50 MeV to 500 MeV for gen­er­a­tion in­tense sec­ondary par­ti­cles such as muon, neu­tron etc.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL029  
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TUPAL030 Improvement of RF Capture with Multi-Turn H− Injection in KURRI FFAG Synchrotron injection, proton, scattering, closed-orbit 1066
 
  • T. Uesugi, Y. Fuwa, Y. Ishi, Y. Kuriyama, Y. Mori, H. Okita
    Kyoto University, Research Reactor Institute, Osaka, Japan
  
  In the KURRI FFAG syn­chro­tron, charge-ex­chang­ing multi-turn in­jec­tion is adopted with a strip­ping foil lo­cated on the closed orbit of in­jec­tion en­ergy. No in­jec­tion bump orbit sys­tem is used and the beam es­capes from the foil ac­cord­ing to the closed-or­bit shift by ac­cel­er­a­tion. The par­ti­cles hit the foil many times and the emit­tance grows up dur­ing the in­jec­tion. In this paper, the cap­ture ef­fi­cien­cies are stud­ied with dif­fer­ent rf process, in­clud­ing adi­a­batic cap­ture.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL030  
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TUPAL076 Result of the First Muon Acceleration with Radio Frequency Quadrupole rfq, experiment, 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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TUZGBF3 Betatron Core Slow Extraction at CNAO betatron, extraction, synchrotron, cavity 1237
 
  • L. Falbo, E. Bressi, S. Foglio, C. Priano
    CNAO Foundation, Milan, Italy
  
  CNAO is the only Ital­ian hadron­ther­apy fa­cil­ity able to treat tu­mors with beams of pro­tons and car­bon ions. Beam is ex­tracted with a mo­men­tum se­lec­tion scheme in which beam en­ters the third order res­o­nance dri­ven by a be­ta­tron core. When ir­ra­di­at­ing a tumor, it is thought as di­vided in the lon­gi­tu­di­nal plane in sev­eral slices while each slice is di­vided in the trans­verse plane in sev­eral spots called vox­els. Con­sid­er­ing the dose uni­for­mity that can be ob­tained dur­ing ex­trac­tion, the ma­chine must ex­tract an av­er­age in­ten­sity re­lated to the voxel that re­quires less dose. There­fore dur­ing a treat­ment, for some slices, a tech­nique is needed to lower the ex­tracted beam in­ten­sity with re­spect to the nom­i­nal one. A way to guar­an­tee the cor­rect av­er­age in­ten­sity ac­cord­ing to the treat­ment plan­ning re­quire­ments, is to in­tro­duce a me­chan­i­cal fil­ter (a de­grader) that re­duces the in­ten­sity of the ac­cel­er­ated par­ti­cles. How­ever this method used in the first treat­ments at CNAO showed some dis­ad­van­tages and it has been re­placed by what has been called the "dy­namic be­ta­tron" method. The paper shows the im­ple­men­ta­tions and the ad­van­tages of this method in the CNAO treat­ments.  
slides icon Slides TUZGBF3 [2.146 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUZGBF3  
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TUPMK012 Acceleration of Charged Particles by Own Field in a Non-Stationary One-Dimensional Stream interface, ECR, electron, operation 1516
 
  • A.S. Chikhachev
    Allrussian Electrotechnical Institute, Moskow, Russia
  
  The be­hav­ior of a non-sta­tion­ary stream of the charged par­ti­cles in­ter­act­ing with own field is stud­ied. For the de­scrip­tion the in­te­gral of the move­ment re­ceived in works * ** - Meshch­er­sky's in­te­gral is used. The ad­di­tional in­te­gral of the move­ment - in­ter­faced to Meshch­er­sky's in­te­gral, nec­es­sary for com­pletely self-agreed de­scrip­tion of a stream of the par­ti­cles in­ter­act­ing with own field is con­structed. The sys­tem of the equa­tions re­duc­ing a prob­lem to the so­lu­tion of sys­tem of the or­di­nary dif­fer­en­tial equa­tions is re­moved. Pri­vate de­ci­sions for po­ten­tial, den­sity of par­ti­cles and den­sity of cur­rent are pro­vided. Ear­lier the prob­lem was stud­ied in work ***.
* Mestschersky J. Astronomische Nachrichten, 1893, T.132, N3153, p. 9.
** Nestschersky ibid, 1902, T.159, N3807, p. 15.
*** Chikhachev A.S., Technical Phisics, 2014, vol 59, N 4, pp 487-493. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMK012  
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TUPML003 Design of an L-band Accelerating Structure for the Argonne Wakefield Accelerator Facility Witness Beam Line Energy Upgrade linac, impedance, coupling, quadrupole 1533
 
  • J.H. Shao, M.E. Conde, D.S. Doran, J.F. Power
    ANL, Argonne, Illinois, USA
  • C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio, USA
  
  The Ar­gonne Wake­field Ac­cel­er­a­tor (AWA) fa­cil­ity has been de­vot­ing much ef­fort to the fun­da­men­tal R&D of two-beam ac­cel­er­a­tion (TBA) tech­nol­ogy with two par­al­lel L-band beam lines. Be­gin­ning from the 70 MeV drive beam line, the high fre­quency (C-band and above) rf power is ex­tracted from the beam by a de­cel­er­at­ing struc­ture (a.k.a. power ex­trac­tor), trans­ferred to an ac­cel­er­at­ing struc­ture in the wit­ness beam line, and used to ac­cel­er­ate the 15 MeV main beam. These high fre­quency ac­cel­er­at­ing struc­tures usu­ally have a small aper­ture to ob­tain high gra­di­ent and high ef­fi­ciency, mak­ing it dif­fi­cult for the low en­ergy main beam to pass. To ad­dress this issue, one pro­posal is to in­crease the main beam en­ergy to above 30 MeV by re­plac­ing the cur­rent wit­ness linac. A 9-cell 𝜋-mode L-band stand­ing-wave ac­cel­er­at­ing struc­ture has there­fore been de­signed to meet the high shunt im­ped­ance and low cost re­quire­ments. In ad­di­tion, the sin­gle-feed cou­pling cell has been op­ti­mized with ad­di­tional sym­met­ri­cal ports to elim­i­nate field dis­tor­tion. The de­tailed de­sign of the new ac­cel­er­at­ing struc­ture will be pre­sented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML003  
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TUPML005 Study of a Dielectric Disk Structure for Short Pulse Two-Beam Acceleration impedance, collider, beam-loading, linear-collider 1539
 
  • J.H. Shao, M.E. Conde, D.S. Doran, J.F. Power
    ANL, Argonne, Illinois, USA
  • C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio, USA
  
  Ar­gonne Flex­i­ble Lin­ear Col­lider (AFLC), a pro­posed 3 TeV elec­tron-positron lin­ear col­lider based on two-beam ac­cel­er­a­tion (TBA) scheme, ap­plies a short pulse length (∼20 ns) to ob­tain a high ac­cel­er­at­ing gra­di­ent (267 MV/m) and a com­pact foot­print (∼18 km). The base­line de­sign of the main ac­cel­er­a­tor sec­tion adopts 26 GHz K-band trav­el­ing-wave di­elec­tric-loaded ac­cel­er­a­tors (DLA) with an rf to beam ef­fi­ciency 𝜂𝑟𝑓 −𝑏𝑒𝑎𝑚 of 27%. Re­cently, an al­ter­na­tive struc­ture which is sim­i­lar to a metal­lic disk-loaded one but with di­elec­tric disks, noted as di­elec­tric disk ac­cel­er­a­tor (DDA), has been in­ves­ti­gated and op­ti­mized, lead­ing to ∼45% im­prove­ment in 𝜂𝑟𝑓 −𝑏𝑒𝑎𝑚. To demon­strate the key tech­nolo­gies, an X-band pro­to­type struc­ture has been de­signed and will be tested at Ar­gonne Wake­field Ac­cel­er­a­tor (AWA) fa­cil­ity with a 300 MW metal­lic power ex­trac­tor. De­tailed com­par­i­son be­tween K-band DLA and DDA for AFLC main ac­cel­er­a­tor as well as the pre­lim­i­nary de­sign of the X-band DDA pro­to­type will be pre­sented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML005  
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TUPML007 Short Pulse High Power RF Generation with an X-Band Dielectric Power Extractor experiment, simulation, 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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TUPML036 ALEGRO, the Advanced LinEar collider study GROup collider, plasma, laser, linear-collider 1619
 
  • P. Muggli
    MPI, Muenchen, Germany
  • B. Cros
    CNRS LPGP Univ Paris Sud, Orsay, France
  
  We briefly de­scribe ac­tiv­i­ties of ALE­GRO, the Ad­vanced Lin­Ear col­lider study GROup.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML036  
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TUPML041 Two-Stage Laser-Driven Plasma Acceleration With External Injection for EuPRAXIA plasma, electron, laser, wakefield 1634
 
  • E.N. Svystun, R.W. Aßmann, U. Dorda, A. Ferran Pousa, T. Heinemann, B. Marchetti, P.A. Walker, M.K. Weikum, J. Zhu
    DESY, Hamburg, Germany
  • A. Ferran Pousa, T. Heinemann, A. Martinez de la Ossa
    University of Hamburg, Hamburg, Germany
  • T. Heinemann
    USTRAT/SUPA, Glasgow, United Kingdom
  
  The Eu­PRAXIA (Eu­ro­pean Par­ti­cle Re­search Ac­cel­er­a­tor with eX­cel­lence In Ap­pli­ca­tions) pro­ject aims at pro­duc­ing a con­cep­tual de­sign for the world­wide plasma-based ac­cel­er­a­tor fa­cil­ity, ca­pa­ble of de­liv­er­ing multi-GeV elec­tron beams with high qual­ity. This ac­cel­er­a­tor fa­cil­ity will be used for var­i­ous user ap­pli­ca­tions such as com­pact X-ray sources for med­ical imag­ing and high-en­ergy physics de­tec­tor tests. Eu­PRAXIA ex­plores dif­fer­ent ap­proaches to plasma ac­cel­er­a­tion tech­niques. Laser-dri­ven plasma wake­field ac­cel­er­a­tion with ex­ter­nal in­jec­tion of an RF-gen­er­ated elec­tron beam is one of the basic re­search di­rec­tions of Eu­PRAXIA. We pre­sent stud­ies of elec­tron beam ac­cel­er­a­tion to GeV en­er­gies by a two-stage laser wake­field ac­cel­er­a­tion with ex­ter­nal in­jec­tion from an RF ac­cel­er­a­tor. Elec­tron beam in­jec­tion, ac­cel­er­a­tion and ex­trac­tion from the plasma, using par­ti­cle-in-cell sim­u­la­tions, are in­ves­ti­gated.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML041  
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TUPML045 Segmented Terahertz Driven Device for Electron Acceleration electron, laser, linac, controls 1642
 
  • D. Zhang
    DESY, Hamburg, Germany
  • A-L. Calendron, H. Cankaya, M. Fakhari, A. Fallahi, Y. Hua, N.H. Matlis, X. Wu, L.E. Zapata
    CFEL, Hamburg, Germany
  • M. Hemmer, F.X. Kärtner
    Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany
  • F.X. Kärtner
    MIT, Cambridge, Massachusetts, USA
  
  Funding: ERC Synergy Grant AXSIS (609920), Deutsche Forschungsgemeinschaft (SPP1840 SOLSTICE and CUI EXC1074), and Gordon and Betty Moore foundation (ACHIP GBMF4744)
We pre­sent a seg­mented THz based de­vice (STEAM) ca­pa­ble of per­form­ing mul­ti­ple high-field op­er­a­tions on the 6D-phase-space of ul­tra­short elec­tron bunches. Using only a few mi­cro­joules of sin­gle-cy­cle THz ra­di­a­tion, we have shown record THz-based ac­cel­er­a­tion of >30 keV of an in­com­ing 55keV elec­tron beam, with a peak ac­cel­er­a­tion field gra­di­ent of around 70 MV/m that is com­pa­ra­ble with that from a con­ven­tional RF ac­cel­er­a­tor. It can be scaled up to GV/m gra­di­ents that can ac­cel­er­ate elec­trons into the MeV regime. At the same time, the STEAM de­vice can also ma­nip­u­late the elec­trons that show high fo­cus­ing gra­di­ent (2 kT/m), com­pres­sion of elec­tron bunches down to 100 fs and streak­ing gra­di­ent of 140 μrad/fs, which of­fers tem­po­ral pro­file char­ac­ter­i­za­tions with res­o­lu­tion below 10 fs. The STEAM de­vice can be fab­ri­cated with reg­u­lar me­chan­i­cal ma­chin­ing tools and sup­ports real-time switch­ing be­tween dif­fer­ent modes of op­er­a­tion. It paves the way for the de­vel­op­ment of THz-based com­pact elec­tron guns, ac­cel­er­a­tors, ul­tra­fast elec­tron dif­frac­tome­ters and Free-Elec­tron Lasers. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML045  
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TUPML047 Optimisation of High Transformer Ratio Plasma Wakefield Acceleration at PITZ plasma, wakefield, laser, electron 1648
 
  • G. Loisch, P. Boonpornprasert, J.D. Good, M. Groß, H. Huck, M. Krasilnikov, O. Lishilin, A. Oppelt, Y. Renier, F. Stephan
    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
  
  The trans­former ratio, the ratio be­tween max­i­mum ac­cel­er­at­ing field and max­i­mum de­cel­er­at­ing field in the dri­ving bunch of a plasma wake­field ac­cel­er­a­tor (PWFA), is one of the key as­pects of this ac­cel­er­a­tion scheme. It not only de­fines the max­i­mum pos­si­ble en­ergy gain of the PWFA but it is also con­nected to the max­i­mum per­cent­age of en­ergy that can be ex­tracted from the dri­ver, which is a lim­it­ing fac­tor for the ef­fi­ciency of the ac­cel­er­a­tor. Since in lin­ear wake­field the­ory a trans­former ratio of 2 can­not be ex­ceeded with sym­met­ri­cal drive bunches, any ratio above 2 is con­sid­ered high. After the first demon­stra­tion of high trans­former ratio ac­cel­er­a­tion in a plasma wake­field at PITZ, the pho­toin­jec­tor test fa­cil­ity at DESY, Zeuthen site, lim­it­ing as­pects of the trans­former ratio are under in­ves­ti­ga­tion. This in­cludes e.g. the oc­cur­rence of bunch in­sta­bil­i­ties, like the trans­verse two stream in­sta­bil­ity, or de­vi­a­tions of the ex­per­i­men­tally achieved bunch shapes from the ideal.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML047  
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TUPML064 Staged Two Beam Acceleration Beam Line Design for the AWA Facility kicker, experiment, gun, laser 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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TUPML079 A Start to End Simulation of the Laser Plasma Wakefield Acceleration Experiment at ESCULAP plasma, electron, laser, wakefield 1731
 
  • K. Wang, C. Bruni, K. Cassou, V. Chaumat, N. Delerue, D. Douillet, S. Jenzer, V. Kubytskyi, P. Lepercq, H. Purwar
    LAL, Orsay, France
  • E. Baynard, M. Pittman
    CLUPS, Orsay, France
  • J. Demailly, O. Guilbaud, S. Kazamias, B. Lucas, G. Maynard, O. Neveu, D. Ros
    CNRS LPGP Univ Paris Sud, Orsay, France
  • D. Garzella
    CEA, Gif-sur-Yvette, France
  • R. Prazeres
    CLIO/ELISE/LCP, Orsay, France
  
  We pre­sent a start to end (s2e) sim­u­la­tion of the Laser­plasma Wake Field Ac­cel­er­a­tor (LPWA) fore­seen as the ES­CU­LAP pro­ject. We use a photo in­jec­tor to pro­duce a 5 MeV 10 pC elec­tron bunch with a du­ra­tion of 1 ps RMS, it is boosted to 10 MeV by a S-band cav­ity and then com­pressed to 74 fs RMS (30 fs FWHM) by a mag­netic com­pres­sion chi­cane (dog­leg). After the dog­leg, a quadru­pole dou­blet and a triplet are uti­lized to match the Twiss pa­ra­me­ters be­fore in­ject­ing into the sub­se­quent plasma wake­field. A 40 TW laser is used to ex­cite plasma wake­field in the 10 cm plasma cell. An op­ti­mized con­fig­u­ra­tion has been de­ter­mined yield­ing at the plasma exit an elec­tron beam at 180 MeV with en­ergy spread of 4.2%, an an­gu­lar di­ver­gence of 0.6 mrad and a du­ra­tion of 4 fs.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPML079  
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WEPAL022 Operating Experience of Water Cooling System in the J-PARC LINAC and RCS linac, diagnostics, klystron, DTL 2203
 
  • K. Suganuma, K. Fujirai, M. Kinsho, P.K. Saha, Y. Yamazaki
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  
  The cool­ing sys­tem for the J-PARC LINAC and RCS uses a total of 25 cir­cu­la­tion pumps to cool the ac­cel­er­a­tor de­vices. In Feb­ru­ary 2017, we ex­pe­ri­enced dam­age of cir­cu­la­tion pumps due to low flow rate, and started the de­vel­op­ment of an ab­nor­mal­ity de­tec­tion sys­tem con­cen­trat­ing on the vi­bra­tion mea­sure­ments of the cir­cu­la­tion pumps. In this re­port, the vi­bra­tion mea­sure­ment re­sults of the coolant cir­cu­la­tion pumps and the de­vel­op­ment sta­tus of ab­nor­mal­ity de­tec­tion through mul­ti­vari­ate analy­sis using vi­bra­tion val­ues are dis­cussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL022  
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THPAF042 Improvement of the Longitudinal Beam Transfer from PS to SPS at CERN cavity, emittance, controls, proton 3060
 
  • A. Lasheen, H. Damerau, J. Repond, M. Schwarz, E.N. Shaposhnikova
    CERN, Geneva, Switzerland
  
  The beam trans­fer from the Pro­ton Syn­chro­tron (PS) to the Super Pro­ton Syn­chro­tron (SPS) at CERN is a crit­i­cal process for the pro­duc­tion of beams for the Large Hadron Col­lider (LHC). A bunch-to-bucket trans­fer is per­formed with the main draw­back that the rf fre­quency in the SPS (200 MHz) is five times higher than the one in the PS (40 MHz). The PS bunches are there­fore short­ened non-adi­a­bat­i­cally be­fore ex­trac­tion by ap­ply­ing a fast rf volt­age in­crease (bunch ro­ta­tion) to fit them into the short rf buck­ets in the SPS. How­ever, par­ti­cles with large am­pli­tude of syn­chro­tron os­cil­la­tions in the PS lon­gi­tu­di­nal phase space are not prop­erly cap­tured in the SPS. They con­tribute to losses at the in­jec­tion plateau and at the start of ac­cel­er­a­tion in the SPS. In this con­tri­bu­tion, we pre­sent mea­sure­ments and sim­u­la­tions per­formed to iden­tify the source of the un­cap­tured par­ti­cles. The tails of the par­ti­cle dis­tri­b­u­tion were char­ac­ter­ized by ap­ply­ing lon­gi­tu­di­nal shav­ing dur­ing ac­cel­er­a­tion. Fur­ther­more, the ro­tated bunch dis­tri­b­u­tion was im­proved by lin­eariz­ing the rf volt­age using a higher-har­monic rf cav­ity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF042  
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THPAF077 Ion-optical Measurements at CRYRING@ESR during Commissioning MMI, injection, simulation, closed-orbit 3161
 
  • O. Geithner, Z. Andelkovic, M. Bai, A. Bräuning-Demian, V. Chetvertkova, O. Chorniy, C. Dimopoulou, W. Geithner, O.E. Gorda, F. Herfurth, M. Lestinsky, S.A. Litvinov, S. Reimann, A. Reiter, M. Sapinski, R. Singh, T. Stöhlker, G. Vorobjev, U. Weinrich
    GSI, Darmstadt, Germany
  • A. Källberg
    Stockholm University, Stockholm, Sweden
  
  CRYRING@​ESR is a heavy ion stor­age ring, which can cool and de­cel­er­ate highly charged ions down to a few 100 keV/u. It has been re­lo­cated from Swe­den to GSI, down­stream of the ex­per­i­men­tal stor­age ring (ESR), within the FAIR pro­ject. The ring will be used as a test fa­cil­ity for FAIR tech­nolo­gies as well as for physics ex­per­i­ments with slow ex­otic ion beams for sev­eral FAIR col­lab­o­ra­tions: SPARC, Bio­Mat, FLAIR and NUS­TAR. CRYRING@​ESR is in its com­mis­sion­ing phase since sum­mer 2016. Sev­eral ion-op­ti­cal mea­sure­ments such as tunes, tune di­a­gram, dis­per­sion, chro­matic­ity and orbit re­sponse ma­trix were per­formed at the ring. The mea­sure­ments will be used for sev­eral pur­poses such as im­prove­ment of the the­o­ret­i­cal model, closed orbit con­trol and cor­rec­tion of un­ac­cept­able mis­align­ments, cal­i­bra­tion co­ef­fi­cients and field er­rors.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF077  
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THPAK034 Practical Betatron Tune Behavior During Acceleration in Scaling FFAG Rings at KURNS booster, betatron, proton, extraction 3287
 
  • Y. Ishi, Y. Fuwa, Y. Kuriyama, Y. Mori, H. Okita, T. Uesugi
    Kyoto University, Research Reactor Institute, Osaka, Japan
  • J.-B. Lagrange
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  
  In scal­ing FFAG* ac­cel­er­a­tors, ide­ally, be­ta­tron tunes are fixed for each closed orbit con­cerned with the cer­tain beam en­ergy. There­fore, they should not vary dur­ing the ac­cel­er­a­tion. How­ever, it is not the case since prac­ti­cal im­ple­men­ta­tions of the mag­netic field can not pro­vide per­fect scal­ing con­di­tions. There are two types of ra­dial scal­ing FFAG ring at Kyoto Uni­ver­sity Re­search Re­ac­tor In­sti­tute: one has no re­turn yokes so called 'yoke free type' adopted by MAIN RING which has a large tune vari­a­tions caus­ing non neg­li­gi­ble beam losses; the other has re­turn yokes and filed clamps adopted by BOOSTER RING which has smaller tune vari­a­tions com­pared with MAIN RING. We re­port the tune mea­sure­ments and cal­cu­la­tions based on 3-d mag­netic field cal­cu­la­tions about these two types of ring and dis­cuss the scal­ing con­di­tions in FFAG ac­cel­er­a­tors.
FFAG* : FFAG stands for fixed filed alternating gradient. It describes one the focusing scheme in the circular accelerator. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK034  
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THPAK065 Application of Transverse-to-Longitudinal Phase-Space-Exchanged Beam Produced from a Nano-Structure Photocathode to a Soft X-Ray Free-Electron Laser cathode, simulation, quadrupole, laser 3379
 
  • A. Lueangaramwong, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • G. Andonian
    RadiaBeam, Santa Monica, California, USA
  • P. Piot
    Fermilab, Batavia, Illinois, USA
  
  Nano-struc­tured cath­odes can form trans­versely mod­u­lated beams which can be sub­se­quently con­verted to tem­po­rally mod­u­lated beam via a trans­verse-to-lon­gi­tu­di­nal phase space-ex­chang­ing beam­line. We demon­strate via nu­mer­i­cal sim­u­la­tion the gen­er­a­tion of trans­versely mod­u­lated beam at the nm scale and in­ves­ti­gate the cor­re­spond­ing en­hance­ment in a soft-X-ray SASE free-elec­tron laser. Our study is sup­ported by start-to-end sim­u­la­tion com­bin­ing WARP, IM­PACT-T and GEN­E­SIS(FEL process) and fo­cuses on the op­ti­miza­tion of the beam­line to pre­serve ini­tial mod­u­la­tion at the nanome­ter level. We also dis­cuss the scal­ing of the con­cept to shorter-wave­lengths.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK065  
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THPAK075 Simulation of Particle Interactions in a High Intensity Radio-Frequency Quadrupole for Molecular Hydrogen Ions rfq, proton, simulation, electron 3405
 
  • M.J. Easton, H.P. Li, Y.R. Lu, Z. Wang
    PKU, Beijing, People's Republic of China
  • J. Qiang
    LBNL, Berkeley, California, USA
  
  High-in­ten­sity deuteron ac­cel­er­a­tors run the risk of deuteron-deuteron in­ter­ac­tions lead­ing to ac­ti­va­tion. For this rea­son, in the com­mis­sion­ing phase, a mol­e­c­u­lar hy­dro­gen ion (H2+) beam is often used as a model for the deuteron beam with­out the ra­di­a­tion risk. How­ever, com­pos­ite ions are sus­cep­ti­ble to par­ti­cle in­ter­ac­tions that do not af­fect sin­gle ions, such as strip­ping of elec­trons and charge ex­change. Such in­ter­ac­tions af­fect the beam dy­nam­ics re­sults, and may lead to pro­duc­tion of sec­ondary par­ti­cles, which in high-in­ten­sity beams may cause dam­age to the ac­cel­er­a­tor and re­duce the qual­ity of the beam. In order to un­der­stand these ef­fects, we have mod­i­fied the IM­PACT-T par­ti­cle track­ing code to in­clude par­ti­cle in­ter­ac­tions dur­ing the track­ing sim­u­la­tion through a high-in­ten­sity con­tin­u­ous-wave (CW) ra­dio-fre­quency quadru­pole (RFQ). This code is also de­signed to be eas­ily ex­ten­si­ble to other in­ter­ac­tions, such as col­li­sions or break-up of heav­ier ions. Pre­lim­i­nary re­sults and pos­si­bil­i­ties for fu­ture de­vel­op­ment will be dis­cussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK075  
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THPAL004 Research and Development of RF System for SC200 Cyclotron cavity, LLRF, cyclotron, simulation 3616
 
  • G. Chen, C. Chao, G. Liu, X.Y. Long, Z. Peng, Y. Song, Y.S. Wang, C.S. Wei, M. Xu, Q. Yang, X. Zhang, Y. Zhao
    ASIPP, Hefei, People's Republic of China
  • L. Calabretta, A.C. Caruso
    INFN/LNS, Catania, Italy
  • O. Karamyshev, G.A. Karamysheva, N.A. Morozov, E. Samsonov, G. Shirkov
    JINR, Dubna, Moscow Region, Russia
  
  A 200MeV com­pact isochro­nous su­per­con­duct­ing cy­clotron, named SC200, for pro­ton ther­apy is under de­vel­op­ment by col­lab­o­ra­tion of ASIPP (Hefei, China) and JINR (Dubna, Rus­sia). The radio fre­quency (RF) sys­tem as one of most sig­nif­i­cant sub­sys­tems in cy­clotron con­sists of ac­cel­er­a­tion cav­ity, low level RF, RF source and trans­mis­sion net­work. SC200 has two cav­i­ties con­nected in the cen­tre, which are op­er­ated at 91.5 MHz with sec­ond har­monic. To meet the re­quired ac­cel­er­a­tion volt­age, the cav­i­ties have been care­fully de­signed with com­prised choices be­tween sev­eral as­pects, such as Q fac­tor, me­chanic sta­bil­ity and so on. The low-level RF (LLRF) sys­tem has been im­ple­mented by using the FPGA to achieve the sig­nif­i­cant ac­cel­er­at­ing volt­age with an am­pli­tude sta­bil­ity of <0.2% and a phase sta­bil­ity of < 0.1 de­gree. The cav­ity and LLRF sys­tem have been tested out­side of cy­clotron, the re­sults will be pre­sented. For fu­ture, the com­mis­sion­ing of whole RF sys­tem will be started after the as­sem­bly of SC200 at the end of 2019.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL004  
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THPAL033 Measurement of the Internal Dark Current in a High Gradient Accelerator Structure at 17 GHz multipactoring, electron, experiment, 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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THPMF081 Intrinsic Emittance of Single Crystal Cathodes photon, electron, cathode, emittance 4263
 
  • S.S. Karkare, H.A. Padmore
    LBNL, Berkeley, California, USA
  • G. Adhikari, W.A. Schroeder
    UIC, Chicago, Illinois, USA
  
  The trans­verse mo­men­tum of elec­trons is con­served dur­ing pho­toe­mis­sion from atom­i­cally or­dered sur­faces of sin­gle crys­tal ma­te­ri­als. Pho­to­cath­odes used in all pho­toin­jec­tors today have dis­or­dered sur­faces and do not ex­ploit this phe­nom­e­non. Re­cently, using this con­ser­va­tion of trans­verse mo­men­tum, sig­nif­i­cant re­duc­tion in in­trin­sic emit­tance was demon­strated from the (111) sur­face of sil­ver*. Here, we pre­sent mea­sure­ments of trans­verse mo­men­tum dis­tri­b­u­tions of elec­trons pho­toemit­ted from the or­dered sur­faces of Ag and Cu sin­gle crys­tals at sev­eral pho­ton en­er­gies. These mea­sure­ments will help in un­der­stand­ing the pho­toe­mis­sion process and show how band-struc­ture and the con­ser­va­tion of trans­verse mo­men­tum can be used to ob­tain fur­ther re­duc­tion in in­trin­sic emit­tance from pho­to­cath­odes.
*Karkare et al., Phys. Rev. Lett. 118, 164802 (2017) 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF081  
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THPMK048 The Design and Construction of a Novel Dual-Mode Dual-Frequency Linac Design operation, impedance, cavity, resonance 4391
 
  • M.H. Nasr, S.G. Tantawi
    SLAC, Menlo Park, California, USA
  
  One promis­ing ap­proach in boost­ing ac­cel­er­a­tors ef­fi­ciency is dual-mode si­mul­ta­ne­ous op­er­a­tion. In our work, the topic of dual-mode ac­cel­er­a­tion is stud­ied from a wider per­spec­tive with new ap­proaches and tools. We pre­sent a new type of ac­cel­er­a­tor struc­tures that op­er­ates si­mul­ta­ne­ously with two modes and two fre­quen­cies. The fre­quen­cies are not con­strained to be har­mon­i­cally re­lated, but rather have a com­mon sub-har­monic. These de­signs will uti­lize a newly de­vel­oped par­al­lel-feed­ing net­work that feeds each in­di­vid­ual ac­cel­er­at­ing cell in­de­pen­dently using a dis­trib­uted feed­ing net­work. As a re­sult, the de­sign prob­lem con­verges to a sin­gle-cell de­sign with iden­ti­cal cells. The cells are de­signed for max­i­mum ef­fi­ciency using new geo­met­ri­cal op­ti­miza­tion that uti­lizes nonuni­form ra­tio­nal B-spline (NURBS) with a se­ries of con­trol points. We will pre­sent a study on the topic for S-band si­mul­ta­ne­ous op­er­a­tion with C-band or X-band.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK048  
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THPMK087 Conceptual Design of the RF System for the Storage Ring and Linac of the New Light Source in Thailand cavity, storage-ring, linac, operation 4505
 
  • N. Juntong, T. Chanwattana, K. Kittimanapun, T. Pulampong, P. Sunwong
    SLRI, Nakhon Ratchasima, Thailand
  
  The new light source fa­cil­ity in Thai­land will be a ring-based light source with the cir­cum­fer­ence of ap­prox­i­mately 300m and an elec­tron en­ergy of 3GeV. The tar­get beam emit­tance is below 1.0 nm·rad with a max­i­mum beam cur­rent of 300mA. The in­jec­tor uti­lizes a full en­ergy C-band linac with a pho­to­cath­ode RF elec­tron gun. The stor­age ring RF sys­tem is based on a 500MHz fre­quency. The EU-HOM damped cav­ity and the new SPring-8 de­sign TM020 cav­ity is the choice of the stor­age ring cav­ity. The RF power unit for stor­age ring can ei­ther be a high-power kly­stron feed­ing all RF cav­i­ties or a com­bi­na­tion of low power IOTs or solid-state am­pli­fiers feed­ing each cav­ity. The high gra­di­ent C-band struc­ture is con­sid­ered as the main ac­cel­er­at­ing struc­ture for linac. The RF power sys­tem for linac will base on kly­stron and a mod­u­lar mod­u­la­tor. De­tails of RF sys­tems op­tions for this new light source pro­ject will be pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK087  
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THPMK147 Measurement of Slice-Emittance of Electron Bunch Using RF Transverse Deflector emittance, injection, experiment, 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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THPML011 Possibilities for Fabricating Polymer Dielectric Laser Accelerator Structures with Additive Manufacturing laser, site, electron, lattice 4671
 
  • E.I. Simakov, R.D. Gilbertson, M.J. Herman, G. Pilania, D.Y. Shchegolkov, E.M. Walker, E. Weis
    LANL, Los Alamos, New Mexico, USA
  • R.J. England, K.P. Wootton
    SLAC, Menlo Park, California, USA
  
  Funding: Los Alamos National Laboratory LDRD Program
We pre­sent re­sults of re­cent stud­ies of new ma­te­ri­als de­signed for the ad­di­tive man­u­fac­tur­ing of ac­cel­er­at­ing struc­tures for di­elec­tric laser ac­cel­er­a­tors (DLAs). Demon­stra­tion of a stand-alone prac­ti­cal DLA re­quires in­no­va­tion in de­sign and fab­ri­ca­tion of ef­fi­cient laser ac­cel­er­a­tor struc­tures and cou­plers. Many com­pli­cated three-di­men­sional struc­tures for laser ac­cel­er­a­tion (such as a long wood­pile struc­ture with cou­plers) are dif­fi­cult to man­u­fac­ture with con­ven­tional mi­cro­fab­ri­ca­tion tech­nolo­gies. LANL has a large ef­fort fo­cused on de­vel­op­ing new ma­te­ri­als and tech­niques for ad­di­tive man­u­fac­tur­ing. The ma­te­ri­als for DLA struc­tures must have high di­elec­tric con­stant (larger than 4), low loss in the in­frared regime, high laser dam­age thresh­old, and be able to with­stand the elec­tron beam dam­age. This pre­sen­ta­tion will dis­cuss the de­vel­op­ment of novel in­frared di­elec­tric ma­te­ri­als that are of in­ter­est for laser ac­cel­er­a­tion and are com­pat­i­ble with ad­di­tive man­u­fac­tur­ing, as well as re­cent ad­vances in ad­di­tive man­u­fac­tur­ing of di­elec­tric wood­pile struc­tures using a Nano­scribe di­rect laser-writ­ing 3D printer. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML011  
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THPML012 Simulations and Measurements of the Wakefield Loading Effect in Argonne Wakefield Accelerator Beamline wakefield, experiment, linac, 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 experiment, wakefield, 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, experiment, simulation, 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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THPML024 Monoenergetic Beam Generated by Laser Accelerator at Peking University laser, proton, quadrupole, experiment 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, target, experiment 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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THPML032 Using Deep Reinforcement Learning for Designing Sub-Relativistic Electron Linac network, electron, linac, cavity 4720
 
  • Shin, S.W. Shin, J.-S. Chai, M. Ghergherehchi
    SKKU, Suwon, Republic of Korea
  
  Gen­er­ally, when de­sign­ing an ac­cel­er­a­tor de­vice, the de­sign is based on the ex­pe­ri­ence and knowl­edge of the de­signer. Most of the de­sign process pro­ceeds by chang-ing the pa­ra­me­ters and look­ing at the trends and then de­ter­min­ing the op­ti­mal val­ues. This process is time-con­sum­ing and te­dious. In order to ef­fi­ciently per­form this te­dious de­sign process, a method using an op­ti­miza­tion al­go­rithm is used. Re­cently, many peo­ple started to get in­ter­ested in the al­go­rithm used in Al­phaGo, which be­came fa­mous when it won the pro­fes­sional Go player de­vel­oped by google The al­go­rithm used in Al­phaGo is an al­go­rithm called re­in­force­ment learn­ing that learns how to get op­ti­mal re­ward in var­i­ous states by mov­ing around a so­lu­tion space that the agent has not told be­fore­hand. In this paper, we will dis­cuss about de­sign­ing an par­ti­cle ac­cel­er­a­tor by ap­ply­ing Deep Q-net­work al­go­rithm which is one kind of deep learn­ing re­in­force­ment learn­ing.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML032  
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THPML042 Integrating the Lorentz Force Law for Highly-Relativistic Particle-in-Cell Simulations plasma, laser, simulation, radiation 4734
 
  • A.V. Higuera, J.R. Cary
    Tech-X, Boulder, Colorado, USA
  • J.R. Cary
    CIPS, Boulder, Colorado, USA
  
  Funding: This work is supported by the DOE under Grants No. DE-SC0011617 and DE-SC0012444, and by DOE/NSF Grant No. DE-SC0012584
In­te­grat­ing the Rel­a­tivis­tic Lorentz Force Law for plasma sim­u­la­tions is an area of cur­rent re­search (*, **, ***). In par­tic­u­lar, re­cent re­search in­di­cates that in­ter­ac­tion with highly-rel­a­tivis­tic laser fields is par­tic­u­larly prob­lem­atic for cur­rent in­te­gra­tion tech­niques (****). Here is pre­sented a spe­cial-pur­pose in­te­gra­tor yield­ing im­proved ac­cu­racy for highly-rel­a­tivis­tic laser-par­ti­cle in­ter­ac­tions. This in­te­gra­tor has been im­ple­mented in the par­ti­cle-in-cell code VSim, and the au­thors pre­sent an ac­cu­racy and per­for­mance com­par­i­son with sev­eral par­ti­cle push meth­ods.
* http://aip.scitation.org/doi/abs/10.1063/1.4979989
** https://arxiv.org/abs/1702.04486
*** https://arxiv.org/abs/1710.09164
**** http://aip.scitation.org/doi/abs/10.1063/1.4905523 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML042  
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THPML043 Optimization of Dielectric Laser-Driven Accelerators laser, electron, simulation, plasma 4737
 
  • C.P. Welsch, M.G. Ibison, Y. Wei
    The University of Liverpool, Liverpool, United Kingdom
  • M.G. Ibison, Y. Wei, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • J.D.A. Smith
    TXUK, Warrington, United Kingdom
  • G.X. Xia
    UMAN, Manchester, United Kingdom
  
  Funding: This project has received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no 289191.
Di­elec­tric laser-dri­ven ac­cel­er­a­tors (DLAs) uti­liz­ing large elec­tric field from com­mer­cial laser sys­tem to ac­cel­er­ate par­ti­cles with high gra­di­ents in the range of GV/m have the po­ten­tial to re­al­ize a first par­ti­cle ac­cel­er­a­tor ‘on a chip'. Dual-grat­ing struc­tures are one of the can­di­dates for DLAs. They can be mass-pro­duced using avail­able nanofab­ri­ca­tion tech­niques due to their sim­pler struc­tural geom­e­try com­pared to other types of DLAs. Apart from the re­sults from op­ti­miza­tion stud­ies that in­di­cate the best struc­tures, this con­tri­bu­tion also in­tro­duces two new schemes that can help fur­ther im­prove the ac­cel­er­at­ing ef­fi­ciency in dual-grat­ing struc­tures. One is to in­tro­duce a Bragg re­flec­tor that can boost the ac­cel­er­at­ing field in the chan­nel, the other ap­plies pulse-front-tilt op­er­a­tion for a laser beam to help ex­tend the in­ter­ac­tion length. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML043  
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THPML051 Electron Acceleration by Plasma Wave in the Presence of a Transversely Propagated Laser with Magnetic Field electron, plasma, laser, wakefield 4749
 
  • M. Yadav, S. C. Sharma
    DELTECH, New Delhi, India
  • D.N. Gupta, M. Kaur
    University of Delhi, Delhi, India
  
  It has been re­vealed that a rel­a­tivis­tic plasma wave, hav­ing an ex­tremely large elec­tric field, may be uti­lized for the ac­cel­er­a­tion of plasma par­ti­cles. The large ac­cel­er­at­ing field gra­di­ent dri­ven by a plasma wave is the basic mo­ti­va­tion be­hind the ac­cel­er­a­tion mech­a­nism. Such a plasma wave can be ex­cited by a sin­gle laser in the form wake­field in laser-plasma in­ter­ac­tions. In this paper, we study the en­hance­ment of elec­tron ac­cel­er­a­tion by plasma wave in pres­ence of a laser* prop­a­gated per­pen­dic­u­lar to the prop­a­ga­tion of the wake wave. Elec­trons trapped in the plasma wave are ef­fec­tively ac­cel­er­ated by the ad­di­tional field of the laser com­bined with wake­field. The ad­di­tional res­o­nance pro­vided by the laser field con­tributes to the large en­ergy gain of elec­trons dur­ing ac­cel­er­a­tion. The res­o­nant en­hance­ment of elec­tron ac­cel­er­a­tion has been val­i­dated by sin­gle par­ti­cle sim­u­la­tions**. The de­pen­dence of en­ergy gain on laser in­ten­sity, laser spot size, ini­tial elec­tron en­ergy, and elec­tron tra­jec­to­ries have been in­ves­ti­gated.
* G. D. Tsakiris, C. Gahn, and V. K. Tripathi, Phys. Plasmas 7, 3017 (2000)
** Maninder Kaur, and D. N. Gupta, IEEE, 45, p 2841 - 2847, (2017)
 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML051  
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THPML058 Recent Results from MICE on Multiple Coulomb Scattering and Energy Loss scattering, emittance, detector, lepton 4766
 
  • P. Franchini
    University of Warwick, Coventry, United Kingdom
  
  Funding: STFC, DOE, NSF, INFN, and CHIPP
Mul­ti­ple Coulomb scat­ter­ing and en­ergy loss are well known phe­nom­ena ex­pe­ri­enced by charged par­ti­cles as they tra­verse a ma­te­r­ial. How­ever, from re­cent mea­sure­ments made by the MuS­cat col­lab­o­ra­tion, it is known that the avail­able sim­u­la­tion codes (GEANT4, for ex­am­ple) over­es­ti­mate the scat­ter­ing of muons in low Z ma­te­ri­als. This is of par­tic­u­lar in­ter­est to the Muon Ion­iza­tion Cool­ing Ex­per­i­ment* (MICE) col­lab­o­ra­tion which has the goal of mea­sur­ing the re­duc­tion of the emit­tance of a muon beam in­duced by en­ergy loss in low Z ab­sorbers. MICE took data with­out mag­netic field suit­able for mul­ti­ple scat­ter­ing mea­sure­ments in the au­tumn of 2015 with the ab­sorber ves­sel filled with xenon and in the spring of 2016 using a lithium-hy­dride ab­sorber. In the au­tumn of 2016 MICE took data with mag­netic fields on and stud­ied the en­ergy loss of muons in a lithium-hy­dride ab­sorber. These data are all com­pared with the Bethe-Bloch for­mula and with the pre­dic­tions of var­i­ous mod­els, in­clud­ing the de­fault GEANT4 model.
*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-THPML058  
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THPML088 Cavity Impedance Reduction Strategies During Multi Cavity Operation in the SIS100 High Intensity Hadron Synchrotron cavity, controls, emittance, resonance 4863
 
  • D. Mihailescu Stoica, D. Domont-Yankulova
    Technische Universität Darmstadt (TU Darmstadt, RMR), Darmstadt, Germany
  • D. Domont-Yankulova, H. Klingbeil
    TEMF, TU Darmstadt, Darmstadt, Germany
  • H. Klingbeil, D.E.M. Lens
    GSI, Darmstadt, Germany
  
  Funding: Supported by GSI Helmholtzzentrum für Schwerionenforschung GmbH
The planned SIS100 heavy ion syn­chro­tron at the GSI Helmholtzzen­trum für Schw­e­ri­o­nen­forschung will pos­sess twenty fer­rite ac­cel­er­at­ing cav­i­ties in its final stage of ex­ten­sion. As at in­jec­tion and at flat top dur­ing slow ex­trac­tion of the planned ac­cel­er­a­tion cy­cles the RF volt­age will be rel­a­tively low, not all cav­i­ties will be ac­tive in this part of op­er­a­tion. It is im­por­tant to analyse the im­pact of the in­ac­tive cav­i­ties on the over­all RF volt­age and sub­se­quently their im­pli­ca­tion on the lon­gi­tu­di­nal par­ti­cle dy­nam­ics. Clas­si­cal ap­proaches for re­duc­ing the beam im­ped­ance con­sist of ac­tive de­tun­ing of the cav­i­ties to pre-de­scribed park­ing fre­quen­cies. The fact that two out of ten buck­ets have to stay empty in all SIS100 sce­nar­ios is of par­tic­u­lar in­ter­est as ad­di­tional fre­quency com­po­nents ap­pear in the ex­ci­ta­tory beam cur­rent, which have to be con­sid­ered when the cav­ity is de­tuned. There­fore multi-cav­ity par­ti­cle track­ing sim­u­la­tions, con­sist­ing of twenty cav­i­ties and their at­tached LLRF con­trol sys­tems, are car­ried out in order to analyse dif­fer­ent pos­si­bil­i­ties to min­i­mize the im­pact on the beam dy­nam­ics and emit­tance growth. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML088  
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THPML091 Design of a High Gradient 60 GHz Dielectric Accelerating Structure experiment, 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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THPML120 Development of Coating Technique for Superconducting Multilayered Structure site, cavity, target, experiment 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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FRXGBF1 Re-Acceleration of Ultra Cold Muon in J-PARC Muon Facility linac, rfq, experiment, 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  
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