Author: Schmidt, Ch.
Paper Title Page
MOPO038 RF Operation Experience at the European XFEL 109
MOOP09   use link to see paper's listing under its alternate paper code  
 
  • J. Branlard, V. Ayvazyan, Ł. Butkowski, M.K. Grecki, M. Hierholzer, M.G. Hoffmann, M. Hoffmann, M. Killenberg, D. Kostin, T. Lamb, L. Lilje, U. Mavrič, M. Omet, S. Pfeiffer, R. Rybaniec, H. Schlarb, Ch. Schmidt, N. Shehzad, V. Vogel, N. Walker
    DESY, Hamburg, Germany
  
  After its suc­cess­ful com­mis­sion­ing which took place dur­ing the first half of 2017, the Eu­ro­pean X-ray free elec­tron laser is in now in reg­u­lar op­er­a­tion de­liv­er­ing pho­tons to users since Sep­tem­ber 2017. This paper pre­sents an overview on the ex­pe­ri­ence gath­ered dur­ing the first cou­ple of years of op­er­a­tion. In par­tic­u­lar, the focus is set on RF op­er­a­tion, main­te­nance ac­tiv­i­ties, avail­abil­ity and typ­i­cal fail­ures. A first look on ma­chine per­for­mance in terms of RF and beam sta­bil­ity, en­ergy reach, ra­di­a­tion re­lated in­ves­ti­ga­tions and mi­cro­phon­ics stud­ies will also be pre­sented.  
slides icon Slides MOPO038 [2.421 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO038  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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MOPO039 Status Update of the Fast Energy Corrector Cavity at FLASH 112
 
  • S. Pfeiffer, J. Branlard, Ł. Butkowski, M. Hierholzer, M. Hoffmann, K. Honkavaara, H. Schlarb, Ch. Schmidt, S. Schreiber, M. Vogt, J. Zemella
    DESY, Hamburg, Germany
  • M. Fakhari
    CFEL, Hamburg, Germany
  
  Funding: The work is part of EuCARD-2, partly funded by the European Commission, GA 312453.
Lin­ear ac­cel­er­a­tor fa­cil­i­ties dri­ving a free-elec­tron laser re­quire fem­tosec­ond pre­ci­sion syn­chro­niza­tion be­tween ex­ter­nal laser sys­tems and the elec­tron beam. Such high pre­ci­sion is re­quired for pump-probe ex­per­i­ments and also for ex­am­ple for the elec­tron bunch in­jec­tion into a plasma bub­ble for laser plasma ac­cel­er­a­tion. An up­grade of the fast in­tra-train beam-based feed­back sys­tem is planned at the Free-Elec­tron Laser FLASH in Ham­burg, Ger­many. This lin­ear ac­cel­er­a­tor is based on su­per­con­duct­ing (SRF) tech­nol­ogy op­er­at­ing with pulse trains of max­i­mum 1 MHz bunch rep­e­ti­tion rate. Ar­rival time fluc­tu­a­tions of the elec­tron beam are cor­rectable by in­tro­duc­ing small en­ergy mod­u­la­tions prior to the mag­netic bunch com­pres­sor. This con­tri­bu­tion fo­cuses on the de­sign and the char­ac­ter­i­za­tion of a nor­mal-con­duct­ing RF (NRF) cav­ity with large band­width, manda­tory to cor­rect fast ar­rival time fluc­tu­a­tions. The cav­ity has re­cently been in­stalled in the FLASH beam­line. First mea­sure­ments with the new cav­ity will be pre­sented. 		 
poster icon Poster MOPO039 [1.884 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO039  
About • paper received ※ 13 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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MOPO102 Progress of MicroTCA.4 based LLRF System of TARLA 220
 
  • C. Gumus, M. Hierholzer, H. Schlarb, Ch. Schmidt
    DESY, Hamburg, Germany
  • A.A. Aksoy, A. Aydin, Ç. Kaya
    Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
  • O.F. Elcim
    Ankara University Institute of Accelerator Technologies, Golbasi, Turkey
  
  The Turk­ish Ac­cel­er­a­tor and Ra­di­a­tion Lab­o­ra­tory in Ankara (TARLA) is con­struct­ing a 40 MeV Free Elec­tron Laser with con­tin­u­ous wave RF op­er­a­tion. DESY is re­spon­si­ble for de­liv­er­ing a turnkey LLRF sys­tem based on Mi­croTCA.4 stan­dard that will be used to con­trol four su­per­con­duct­ing (SC) TESLA type cav­i­ties as well as the two nor­mal con­duct­ing buncher cav­i­ties. This highly mod­u­lar sys­tem is fur­ther used to con­trol the me­chan­i­cal tun­ing of the SC cav­i­ties by con­trol of piezo ac­tu­a­tors and me­chan­i­cal motor tuners. With the usage of ChimeraTK frame­work, in­te­gra­tion to EPICS con­trol sys­tem is also im­ple­mented. This poster de­scribes the sys­tem setup and in­te­gra­tion to the ex­ist­ing ac­cel­er­a­tor en­vi­ron­ment with hard­ware and soft­ware com­po­nents along with the lat­est up­dates from the fa­cil­ity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO102  
About • paper received ※ 10 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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MOPO104 LLRF R&D Towards CW Operation of the European XFEL 223
SPWR026   use link to see paper's listing under its alternate paper code  
 
  • A. Bellandi, V. Ayvazyan, J. Branlard, C. Gumus, S. Pfeiffer, K.P. Przygoda, R. Rybaniec, H. Schlarb, Ch. Schmidt, J.K. Sekutowicz
    DESY, Hamburg, Germany
  • W. Cichalewski
    TUL-DMCS, Łódź, Poland
  
  The ever grow­ing re­quest for ma­chines with a higher av­er­age beam pulse rate and also with a re­laxed (< 1 MHz) pulse sep­a­ra­tion calls for su­per­con­duct­ing linacs that op­er­ate in Long Pulse (LP) or Con­tin­u­ous Wave (CW) mode. For this pur­pose the Eu­ro­pean X-ray Free Elec­tron Laser (Eu­ro­pean XFEL) could be up­graded to add the abil­ity to run in CW/LP mode. Cryo Mod­ule Test Bench (CMTB) is a fa­cil­ity used to per­form tests on su­per­con­duct­ing cav­ity cry­omod­ules. Be­cause of the in­ter­est in up­grad­ing Eu­ro­pean XFEL to a CW ma­chine, CMTB is now used to per­form stud­ies on XM-3, a 1.3 GHz Eu­ro­pean XFEL-like cry­omod­ule with mod­i­fied cou­pling that is able to run with very high qual­ity fac­tor (QL = 10E7…10E8) val­ues. The RF power source al­lows run­ning the cav­i­ties at gra­di­ents larger than 16 MV/m. Be­cause of the QL and gra­di­ent val­ues in­volved in these tests, de­tun­ing ef­fects like me­chan­i­cal res­o­nances and mi­cro­phon­ics be­came more chal­leng­ing to reg­u­late. The goal is then to de­ter­mine the ap­pro­pri­ate set of pa­ra­me­ters for the LLRF con­trol sys­tem to keep the error to be less than 0.01° in phase and 0.01% in am­pli­tude.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO104  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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TUPO132 Implementation of the Beam Loading Compensation Algorithm in the LLRF System of the European XFEL 594
 
  • Ł. Butkowski, J. Branlard, M. Omet, R. Rybaniec, H. Schlarb, Ch. Schmidt
    DESY, Hamburg, Germany
  
  In the Eu­ro­pean XFEL, a max­i­mum num­ber of 2700 elec­tron bunches per RF pulse with beam cur­rents up to 4.5mA can be ac­cel­er­ated. Such large beam cur­rents can cause a sig­nif­i­cant drop of the ac­cel­er­at­ing gra­di­ents, which re­sults in large en­ergy changes across the macro-pulse. But, the elec­tron bunch en­er­gies should not de­vi­ate from the nom­i­nal en­ergy to guar­an­tee sta­ble and re­pro­ducible gen­er­a­tion of pho­ton pulses for the Eu­ro­pean XFEL users. To over­come this issue, the Low Level RF sys­tem (LLRF) com­pen­sates in real-time the beam per­tur­ba­tion using a Beam Load­ing Com­pen­sa­tion al­go­rithm (BLC) min­i­miz­ing the tran­sient gra­di­ent vari­a­tions. The al­go­rithm takes the charge in­for­ma­tion ob­tained from beam di­ag­nos­tic sys­tems e.g. Beam Po­si­tion Mon­i­tors (BPM) and in­for­ma­tion from the tim­ing sys­tem. The BLC is a part of the LLRF con­troller im­ple­mented in the FPGA. The ar­ti­cle pre­sents the im­ple­men­ta­tion of the al­go­rithm in the FPGA and shows the re­sults achieved with the BLC in the Eu­ro­pean XFEL.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO132  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)