Author: Katayama, R.
Paper Title Page
MOPMB033 Efforts to Suppress Field Emission in SRF Cavities at KEK 167
 
  • M. Omet, H. Araki, T. Dohmae, H. Ito, R. Katayama, K. Umemori, Y. Yamamoto
    KEK, Ibaraki, Japan
  
  Our main ob­jec­tive is to achieve as high as pos­si­ble qual­ity fac­tors Q₀ and max­i­mal ac­cel­er­at­ing volt­ages Eacc within 1.3 GHz su­per­con­duct­ing radio fre­quency (SRF) cav­i­ties. Be­side an ad­e­quate sur­face treat­ment, key to achieve good per­for­mance is a proper as­sem­bly in the clean room prior cav­ity test­ing or op­er­a­tion. In this con­tri­bu­tion we pre­sent the meth­ods and re­sults of our ef­forts to get a bet­ter un­der­stand­ing of our clean room en­vi­ron­ment and the par­tic­u­late gen­er­a­tion caused dur­ing the as­sem­bly work. Fur­ther­more, we pre­sent the mea­sures taken to sup­press filed emis­sion, fol­lowed by an analy­sis of ver­ti­cal test re­sults of the last six years.  
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DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB033  
About • Received ※ 14 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 02 September 2023 — Issue date ※ 02 September 2023
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TUPTB029 Measurement of Particulates under Slow Pumping after High Pressure Rinsing of Superconducting Cavity by Using Modified Slow Pumping System 458
 
  • H. Sakai, E. Kako, R. Katayama, K. Umemori
    KEK, Ibaraki, Japan
  
  Funding: This research was partially supported by the research fund from Ministry of Education, Culture, Sports, Science and Technology (MEXT).
Slow pump­ing sys­tem was used for par­ti­cle free vac­uum pump­ing in Su­per­con­duct­ing rf ac­cel­er­a­tor. In KEK, re­cently slow pump­ing sys­tem was de­vel­oped for the cry­omod­ule as­sem­bly work for STF 9-cell cav­i­ties and worked well to re­duce the par­tic­u­lates move­ments under pump­ing. How­ever, this slow pump­ing sys­tem want to be used for prepa­ra­tion of ver­ti­cal test. Be­fore as­sem­bly work in clean room for ver­ti­cal test, we nor­mally apply high pres­sure rins­ing. There were many wa­ters in the cav­ity. There­fore, we kept one night to dry in­side cav­ity in clean room. Un­for­tu­nately, there were some wa­ters in the cav­ity even though we kept dry­ing in clean room for one night. This water might make some icing under pump­ing and stop pump­ing in mass flow meter, which used for slow pump­ing to con­trol the mass flow. There­fore, we mod­ify the slow pump­ing sys­tem to be ro­bust under slow pump­ing even when water ex­ists in the cav­ity. In this paper, we pre­sent the mod­i­fied slow pump­ing sys­tem in KEK and the re­sults of the vac­uum trend through slow pump­ing of 9-cell su­per­con­duct­ing cav­ity. Under slow pump­ing, we mea­sure the par­tic­u­lates after high pres­sure rins­ing by using vac­uum par­ti­cle mon­i­tor. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB029  
About • Received ※ 16 June 2023 — Revised ※ 26 June 2023 — Accepted ※ 21 August 2023 — Issue date ※ 22 August 2023
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