Author: Regnaud, S.
Paper Title Page
MOPAB388 Status of the High Power Couplers for ESS Elliptical Cavities 1186
 
  • C. Arcambal, P. Bosland, G. Devanz, T. Hamelin, C. Madec, C. Marchand, M. Oublaid, G. Perreu, C. Servouin, C. Simon
    CEA-IRFU, Gif-sur-Yvette, France
  • M. Baudrier, C. Mayri, S. Regnaud, T.V. Vacher
    CEA-DRF-IRFU, France
 
  In the frame­work of the Eu­ro­pean Spal­la­tion Source (ESS), CEA Paris-Saclay is re­spon­si­ble for the de­liv­ery of 30 cry­omod­ules (9 medium beta (β = 0.67) and 21 high beta (β = 0.86) ones). Each cry­omod­ule con­tains 4 el­lip­ti­cal cav­i­ties equipped with a radio fre­quency power cou­pler. The ESS nom­i­nal pulse is 1.1 MW max­i­mum peak power over a width of 3.6 ms at a rep­e­ti­tion rate of 14 Hz. The de­sign of the cou­plers for medium beta and for high beta cav­i­ties is the same, ex­cept a small dif­fer­ence of the an­tenna pen­e­tra­tion to ad­just the Qext. The mass pro­duc­tion of the 120 cou­plers started and all the medium beta cou­plers have been con­di­tioned at room tem­per­a­ture. The first cry­omod­ules equipped with the power cou­plers were suc­cess­fully tested at high RF power and with cav­i­ties at 2K reach­ing the ESS nom­i­nal pulse. The main issue at the start of the se­ries pro­duc­tion could be fixed and it was due to bad TiN coat­ings that caused ab­nor­mal di­elec­tric losses in the win­dow. Thus, this paper deals with the TiN coat­ing de­fect, pre­sents the con­di­tion­ing pro­ce­dure and gives a con­di­tion­ing re­port of these 36 cou­plers.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB388  
About • paper received ※ 19 May 2021       paper accepted ※ 24 May 2021       issue date ※ 18 August 2021  
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