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TY - CONF AU - Sakai, H. AU - Ebisawa, T. AU - Kako, E. AU - Kasugai, A. AU - Konomi, T. AU - Umemori, K. AU - Yamamoto, Y. ED - Michel, Peter ED - Arnold, André ED - Schaa, Volker RW TI - Improvement of a Clean Assembly Work for Superconducting RF Cryomodule and Its Application to the KEK-STF Cryomodule J2 - Proc. of SRF2019, Dresden, Germany, 30 June-05 July 2019 CY - Dresden, Germany T2 - International Conference on RF Superconductivity T3 - 19 LA - english AB - 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] and STF cryomodule also met the degradation after the cryomodule assembly [2]. Some dusts 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. In this paper, first we introduce some trials for the improved clean assembly work to SRF cavity by re-examining our clean assembly work and vacuum work. For example, slow pumping system with vacuum particle monitor was developed to know and control the particle movement during slow pumping and venting. Next we show the application of this improved work to the STF re-assemble cryomodule work in KEK. PB - JACoW Publishing CP - Geneva, Switzerland SP - 721 EP - 725 KW - cryomodule KW - cavity KW - vacuum KW - controls KW - SRF DA - 2019/08 PY - 2019 SN - "" SN - 978-3-95450-211-0 DO - doi:10.18429/JACoW-SRF2019-TUP104 UR - http://jacow.org/srf2019/papers/tup104.pdf ER -