Author: Cichalewski, W.
Paper Title Page
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  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPO029 Highlights of the XM-3 Cryomodule Tests at DESY 388
 
  • J. Branlard, V. Ayvazyan, A. Bellandi, J. Eschke, C. Gumus, D. Kostin, K.P. Przygoda, H. Schlarb, J.K. Sekutowicz
    DESY, Hamburg, Germany
  • W. Cichalewski
    TUL-DMCS, Łódź, Poland
  
  To in­ves­ti­gate the fea­si­bil­ity of the con­tin­u­ous wave (cw) up­grade of the Eu­ro­pean XFEL (E-XFEL) DESY, on-go­ing tests are per­formed on E-XFEL pro­to­type and pro­duc­tion cry­omod­ules since 2011. For these stud­ies, DESY’s Cryo-Mod­ule Test Bench (CMTB) has been equipped with a 105 kW cw op­er­at­ing IOT in ad­di­tion to the 10MW pulsed kly­stron, mak­ing CMTB a very flex­i­ble test stand, en­abling both cw and pulse op­er­a­tion. For these tests, E-XFEL-like LLRF elec­tron­ics is used to sta­bi­lize am­pli­tude and phase of the volt­age Vec­tor Sum (VS) of all 8 cav­i­ties of the cry­omod­ule under test. The cry­omod­ule most often tested is the pre-se­ries XM-3, unique since it is hous­ing one fine grain nio­bium and seven large grain nio­bium cav­i­ties. In au­tumn 2017, ad­di­tional spac­ers were in­stalled on all 8 input cou­plers to in­crease the max­i­mum reach­able loaded qual­ity fac­tor Ql be­yond 2·107. With higher Ql, up to 6·107 for 6 cav­i­ties and 2.7·107 for 2 cav­i­ties, we have in­ves­ti­gated the VS sta­bil­ity and SRF-per­for­mance of this cry­omod­ule under var­i­ous con­di­tions of cool­ing down rate and op­er­a­tion tem­per­a­ture 1.65K, 1.8K and 2K, at gra­di­ents up to ca. 18MV/m. The re­sults of these tests are pre­sented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO029  
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)