Author: Blivet, S.
Paper Title Page
MOPAB392 Alternative RF Tuning Methods Performed on Spoke Cavities for ESS and MYRRHA Projects 1196
 
  • P. Duchesne, S. Blivet, G. Olivier, G. Olry, T. Pépin-Donat
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
 
  In order to ob­tain the tar­get fre­quency in op­er­a­tion, the res­o­nant fre­quency of su­per­con­duct­ing ra­diofre­quency cav­i­ties is con­trolled and ad­justed from the man­u­fac­tur­ing to the end of prepa­ra­tion phase. Reach­ing this right fre­quency can be chal­leng­ing due to the nar­row fre­quency range de­fined by the tun­ing sen­si­tiv­ity of the cav­ity and the ca­pa­bil­ity of the tuner. Me­chan­i­cal de­for­ma­tion until plas­tic­ity is at­tained is of great in­ter­est to tune SRF cav­i­ties when large fre­quency shift is needed. But once a cav­ity is dressed with its he­lium tank, the only ac­ces­si­ble part is its beam pipe, re­duc­ing the me­chan­i­cal ac­tion to a push/pull ac­tion. This lim­ited pos­si­bil­ity has hence to be skil­fully as­so­ci­ated with chem­i­cal etch­ing. An orig­i­nal me­chan­i­cal tun­ing of Spoke dressed cav­i­ties con­sists in in­creas­ing the pres­sure in­side the he­lium tank to in­duce a per­ma­nent de­for­ma­tion of the cav­ity walls. The fre­quency shift in­duced by non­lin­ear de­for­ma­tion is nu­mer­i­cally eval­u­ated in order to de­ter­mine the pres­sure in­cre­ments. Both meth­ods were suc­cess­fully per­formed on the cav­i­ties of the ESS ac­cel­er­a­tor and of the Myrrha pro­ject.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB392  
About • paper received ※ 20 May 2021       paper accepted ※ 25 June 2021       issue date ※ 17 August 2021  
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