TUP051 　高周波加速構造　 8月1日 第1,2,3,4会議室他 13:00 - 15:00

Field emission抑制のための超伝導空洞組立のクリーン作業改善に向けて

Improvement for clean assembly work about superconducting RF cavity & cryomodule to suppress field emission

○阪井 寛志，梅森 健成，加古 永治，許斐 太郎（高エネルギー加速器研究機構），沢村 勝（量子科学技術研究開発機構），篠江 憲治，野上 隆史，古屋 貴章，本田 融（高エネルギー加速器研究機構）

○Hiroshi Sakai, Kensei Umemori, Eiji Kako, Taro Konomi (KEK), Masaru Sawamura (QST), Kenji Shinoe, Takashi Nogami, Takaaki Furuya, Tohru Honda (KEK)

We usually encountered the degradation of the superconducting RF cavities on the cryomodule test even though the performance of these cavities was good on the vertical test. In reality, the degradation of Q-values of two cavities of cERL main-linac were observed after cryomodule assembly in KEK [1]. Some dust and invisible particles might enter the cavity and generate field emission during the assembly work. Field emission is the most important cause of this degradation. It is crucially important not to degrade the cavity performance for not only vertical test but also the cryomodule operation after string assembly work of the cryomodule. In this paper, first we show what work produces the field emission source during assembly work of the cryomodule construction in detail from our experience. Next we introduce some trials for the improved clean assembly work to SRF cavity by re-examining our clean assembly work and considering the elaborated clean work in the other laboratory, like EURO-XFEL in DESY, to overcome the degradation by field emission. [1] H.Sakai et al., Proc. of SRF2013, Paris, 2013, p. 678, paper TUP019.