Keyword: pick-up
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MOPOPT016 Update of the Bunch Arrival Time Monitor at ELBE laser, electron, controls, feedback 260
 
  • M. Kuntzsch, A. Maalberg, A. Schwarz, K. Zenker
    HZDR, Dresden, Germany
  • M.K. Czwalinna, J. Kral
    DESY, Hamburg, Germany
  
  The bunch ar­rival time mon­i­tor (BAM) at the ra­di­a­tion source ELBE has been up­graded twofold. In order to achieve a higher pre­ci­sion a new fron­tend has been de­signed, based on a de­vel­op­ment by DESY, that uses state of the art 50 GHz elec­tro-op­ti­cal mod­u­la­tors (EOMs). The fron­tend al­lows for ther­mal con­trol of crit­i­cal com­po­nents and mon­i­tor­ing of sys­tem pa­ra­me­ters. The mod­u­lated EOM sig­nals and mon­i­tor­ing data are dis­trib­uted to a new read­out elec­tronic. The new Mi­croTCA-based re­ceiveris based on a ded­i­cated FMC card de­vel­oped at DESY that is in­stalled on an FMC25 car­rier board. The ar­rival time is cal­cu­lated on a FPGA with low la­tency and can be used for ma­chine di­ag­nos­tic. The code has been adapted to en­able the pro­cess­ing of a data stream of the con­tin­u­ous train of elec­tron bunches, al­low­ing for the im­ple­men­ta­tion of a cw beam based feed­back in a next step. The con­tri­bu­tion will de­scribe the BAM setup as well as the per­for­mance mea­sured at the ELBE ac­cel­er­a­tor.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT016  
About • Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 01 July 2022
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MOPOPT019 Wakefield Studies for a Bunch Arrival-Time Monitor Concept with Rod-Shaped Pickups on a Printed Circuit Board for X-Ray Free-Electron Lasers FEL, wakefield, electron, simulation 271
 
  • B.E.J. Scheible, A. Penirschke
    THM, Friedberg, Germany
  • W. Ackermann, H. De Gersem
    TEMF, TU Darmstadt, Darmstadt, Germany
  • M.K. Czwalinna, H. Schlarb
    DESY, Hamburg, Germany
  
  Funding: This work is supported by the German Federal Ministry of Education and Research (BMBF) under contract No. 05K19RO1.
The Eu­ro­pean XFEL (Eu­XFEL) and other no­table X-ray Free-Elec­tron Laser fa­cil­i­ties rely on an all-op­ti­cal syn­chro­niza­tion sys­tem with elec­tro-op­ti­cal bunch ar­rival-time mon­i­tors (BAM). The cur­rent BAMs were bench­marked with a res­o­lu­tion of 3.5 fs for nom­i­nal 250 pC bunches at the Eu­XFEL, in­clud­ing jit­ter of the op­ti­cal ref­er­ence sys­tem. The ar­rival-time jit­ter could be re­duced to about 10 fs with a beam-based feed­back sys­tem. For fu­ture ex­per­i­ments at the Eu­XFEL the bunch charge will be de­creased to a level where the ex­ist­ing sys­tem’s ac­cu­racy will no longer be suf­fi­cient. In sim­u­la­tions a con­cept based on rod-shaped pick­ups mounted on a printed cir­cuit board in­di­cated its po­ten­tial for such low charge ap­pli­ca­tions. For the fea­si­bil­ity of the pro­posed de­sign, its con­tri­bu­tion to the total im­ped­ance is es­sen­tial. In this work the de­sign and an in­ter­me­di­ate ver­sion are com­pared to state-of-the-art BAM re­gard­ing their wake po­ten­tial. Fur­ther­more, mea­sures to mit­i­gate wake­fields are dis­cussed. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT019  
About • Received ※ 08 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 05 July 2022  
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TUPOST007 New Generation of Very Low Noise Beam Position Measurement System for the LHC Transverse Feedback feedback, controls, operation, injection 849
 
  • D. Valuch
    CERN, Meyrin, Switzerland
  • V. Stopjakova
    Slovak University of Technology (STU), Faculty of Electrical Engineering and Information Technology, Bratislava, Slovak Republic
  
  Re­cent stud­ies showed that the trans­verse feed­back sys­tem noise floor in the Large Hadron Col­lider (LHC) must be re­duced by at least fac­tor of two in order to op­er­ate the ma­chine with large beam-beam tune shift as fore­seen in the High Lu­mi­nos­ity (HL) LHC. Also, the fu­ture feed­back sys­tem fore­seen to sup­press the LHC Crab Cav­ity noise re­lies on im­proved noise per­for­mance of the beam po­si­tion mea­sure­ment sys­tem. An up­grade pro­gram was launched to lower the LHC trans­verse feed­back sys­tem noise floor dur­ing the LHC Long Shut­down II. A new gen­er­a­tion, very low noise beam po­si­tion mea­sure­ment mod­ule was de­vel­oped and tested with beam. In­no­v­a­tive meth­ods in the RF re­ceiver, dig­i­tal sig­nal pro­cess­ing, thor­ough op­ti­miza­tion of every el­e­ment in the sig­nal chain from pickup to the kick­ers al­lowed to achieve a sig­nif­i­cant re­duc­tion of the sys­tem noise floor. This un­prece­dented noise per­for­mance opens also new pos­si­bil­i­ties for aux­il­iary in­stru­ments, using the po­si­tion data from the trans­verse feed­back. The paper pre­sents the new sys­tem, no­table im­ple­men­ta­tion de­tails and mea­sured per­for­mance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST007  
About • Received ※ 18 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 30 June 2022
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TUPOST037 Reconstruction of Transverse Phase Space From Transverse Feedback Data for Real Time Extraction of Vital LHC Machine Parameters feedback, real-time, injection, betatron 937
 
  • G. Kotzian, M.E. Soderen, P.S. Solvang, D. Valuch
    CERN, Meyrin, Switzerland
  • V. Stopjakova
    Slovak University of Technology (STU), Faculty of Electrical Engineering and Information Technology, Bratislava, Slovak Republic
  
  The LHC trans­verse feed­back sys­tem (ADT) pro­vides bunch by bunch, turn by turn, nor­mal­ized and dig­i­tized beam po­si­tion sig­nals from four pick-ups per plane and for each beam. To­gether with al­ready ex­ist­ing pow­er­ful com­puter-based ob­ser­va­tion sys­tems, this data can be used to re­con­struct in real-time the trans­verse phase space co­or­di­nates of the cen­tre-of-charges, for each in­di­vid­ual bunch. Such in­for­ma­tion is ex­tremely valu­able for ma­chine op­er­a­tion, or trans­verse in­sta­bil­ity di­ag­nos­tics. This paper aims on dis­cussing and eval­u­at­ing meth­ods of com­bin­ing four po­si­tion sig­nals for such analy­sis in the pres­ence of noise and with ac­tive trans­verse feed­back. Com­par­isons are made based on the ex­trac­tion of vital pa­ra­me­ters like the frac­tional tune or trans­verse ac­tiv­ity. An­a­lyt­i­cal and nu­mer­i­cal re­sults are fur­ther bench­marked against real beam data.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST037  
About • Received ※ 20 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 04 July 2022
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TUPOTK033 First RF Measurements of Planar SRF Thin Films with a High Throughput Test Facility at Daresbury Laboratory cavity, SRF, MMI, site 1283
 
  • D.J. Seal, G. Burt, P. Goudket, O.B. Malyshev, B.S. Sian, R. Valizadeh
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • G. Burt, D.J. Seal, B.S. Sian
    Lancaster University, Lancaster, United Kingdom
  • P. Goudket, O.B. Malyshev, R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • P. Goudket
    ESS, Lund, Sweden
  • H.S. Marks
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  
  The re­search on su­per­con­duct­ing thin films for fu­ture radio fre­quency (RF) cav­i­ties re­quires mea­sur­ing the RF prop­er­ties of these films. How­ever, coat­ing and test­ing thin films on full-sized cav­i­ties is both chal­leng­ing and time­con­sum­ing. As a re­sult, films are typ­i­cally de­posited on small, flat sam­ples and char­ac­terised using a test cav­ity. At Dares­bury Lab­o­ra­tory, a fa­cil­ity for test­ing 10 cm di­am­e­ter sam­ples has re­cently been com­mis­sioned. The cav­ity uses RF chokes to allow phys­i­cal and ther­mal sep­a­ra­tion be­tween it­self and the sam­ple under test. The fa­cil­ity al­lows for sur­face re­sis­tance mea­sure­ments at a res­o­nant fre­quency of 7.8 GHz, at tem­per­a­tures down to 4 K, max­i­mum RF power of 1 W and peak mag­netic fields of a few mT. The main ad­van­tage of this sys­tem is the sim­ple sam­ple mount­ing pro­ce­dure due to no phys­i­cal weld­ing be­tween the sam­ple and test cav­ity. This al­lows for a fast turn­around time of two to three days be­tween sam­ples. As such, this sys­tem can be used to quickly iden­tify which sam­ples are per­form­ing well under RF and should re­quire fur­ther test­ing at higher gra­di­ent. De­tails of re­cent up­grades to this fa­cil­ity, to­gether with mea­sure­ments of both bulk nio­bium and thin film sam­ples, will be pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK033  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 30 June 2022 — Issue date ※ 02 July 2022
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WEPOST050 Further Measurements of Beam-Beam Interactions in a Gear-Changing System in DESIREE experiment, synchrotron, collider, space-charge 1810
 
  • E.A. Nissen
    JLab, Newport News, Virginia, USA
  • A. Källberg, A. Simonsson
    Stockholm University, Stockholm, Sweden
  
  Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a license to publish or reproduce this manuscript.
In this work we de­tail ex­per­i­ments per­formed on a gear-chang­ing sys­tem using the Dou­ble Elec­tro­Sta­tic Ion Ring Ex­pEr­i­ment (DE­SIREE). A gear-chang­ing sys­tem is one where there are dif­fer­ent har­monic num­bers in each ring. This ex­per­i­ment used car­bon and ni­tro­gen beams in a 4 on 3 gear-chang­ing arrange­ment, with the last bunch of each left off. The bunch length can be mea­sured and syn­chro­tron mo­tion de­tected. We per­formed this mea­sure­ment on three dif­fer­ent val­ues of car­bon cur­rent, and pre­sent the dif­fer­ences in the bunch length fre­quency spec­trum here, which cor­re­spond to twice the syn­chro­tron fre­quen­cies. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST050  
About • Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 30 June 2022
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WEPOTK022 Horizontal Beam Response at Extraction Conditions at the Heidelberg Ion-Beam Therapy Centre extraction, simulation, resonance, sextupole 2096
 
  • E.C. Cortés García, E. Feldmeier, Th. Haberer
    HIT, Heidelberg, Germany
  
  The Hei­del­berg Ion-Beam Ther­apy Cen­tre’s syn­chro­tron makes use of the sex­tu­pole dri­ven RF-KO method near the third-or­der res­o­nance in order to slowly ex­tract the beam that is de­liv­ered to the pa­tients. The hor­i­zon­tal beam re­sponse of a coast­ing beam was stud­ied ex­per­i­men­tally and with sim­u­la­tions at ex­trac­tion con­di­tions in order to de­duce re­gions of in­ter­est for an op­ti­mal ex­ci­ta­tion sig­nal spec­trum. Two nar­row fre­quency re­gions were found were the beam re­acts co­her­ently. With these in­for­ma­tion an RF sig­nal was pro­posed for the res­o­nant slow ex­trac­tion.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK022  
About • Received ※ 17 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 03 July 2022
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FRIXGD1 Status and Prospects in Fast Beam-Based Feedbacks feedback, kicker, cavity, hadron 3112
 
  • W. Höfle
    CERN, Meyrin, Switzerland
  
  Fast beam-based Feed­back sys­tems play an im­por­tant role in cir­cu­lar ac­cel­er­a­tors to mit­i­gate in­sta­bil­i­ties and re­duce the im­pact of in­jec­tion os­cil­la­tions and per­tur­ba­tions on beam qual­ity, both in the lon­gi­tu­di­nal and trans­verse planes. The sta­tus and prospects of such beam-based feed­back sys­tems for cir­cu­lar ac­cel­er­a­tors are re­viewed. This in­cludes progress to­wards the fun­da­men­tal lim­its in noise and feed­back gain and the pos­si­bil­i­ties of mod­ern dig­i­tal sys­tems to ex­tract large amounts of data that can be used to char­ac­terise beam prop­er­ties. The talk con­cen­trates on ma­chines with hadrons and gives an out­look on pos­si­ble de­vel­op­ments for fu­ture ac­cel­er­a­tor pro­jects under study.  
slides icon Slides FRIXGD1 [3.562 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-FRIXGD1  
About • Received ※ 08 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022  
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