SRF Technology - Cryomodule
in-situ processing
Paper Title Page
THP064 The Cryostat Results of Carbon Contamination and Plasma Cleaning for the Field Emission on the SRF Cavity 1038
 
  • A.D. Wu, Q.W. Chu, H. Guo, Y. He, S.C. Huang, C.L. Li, F. Pan, Y.K. Song, T. Tan, P.R. Xiong, W.M. Yue, S.H. Zhang, H.W. Zhao
    IMP/CAS, Lanzhou, People’s Republic of China
 
  The field emission effect is the mainly limitation for the operating of SRF cavities in higher gradient with stability. In this paper, the experiments were performed to evaluate the impact of the carbon contaminants and plasma cleaning on the performance of SRF cavity. Contamination mechanism was classified into cryogenic adsorption with weak strength and chemical deposition with strong strength. For the weak strength condition, the methane was injected into the SRF cavity during vertical test to make a cryogenic adsorption layer on the inner surface of the cavity. The results revealed that the performance of SRF cavity degraded by methane physical adsorption, but the performance can be recovered by thermal cycle the cavity to 300K and pump methane out. For the strong strength condition, the chemical deposited dirty layer of carbon contamination was produced by using of Ar/CH4 mixed PECVD method, and the SRF cavity performance was deteriorated by the severe field emission. Finally, carbon deposited cavity was treated by the Ar/O2 plasma, and its results revealed that the field emission removed greatly and the gradient was increased.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP064  
About • paper received ※ 20 June 2019       paper accepted ※ 01 July 2019       issue date ※ 14 August 2019  
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FRCAB6 The Effect of Helium Processing and Plasma Cleaning for Low Beta HWR Cavity 1228
THP065   use link to see paper's listing under its alternate paper code  
 
  • S.C. Huang, Q.W. Chu, Y. He, C.L. Li, A.D. Wu, S.X. Zhang
    IMP/CAS, Lanzhou, People’s Republic of China
 
  The commissioning of the 25 MeV high power and high intensity proton Linac demo for CiADS showed that the performance of the SRF cavities was mainly limited by field emission inside the cavities. Therefore, the techniques of helium processing and reactive oxygen plasma cleaning have been developed to mitigate field emission issues. We performed an experiment with a low beta HWR cavity exposed to air directly and processed by helium and reactive oxygen. In this paper, the details of the experiment will be described, the efficiency of helium processing and plasma cleaning will be compared and discussed  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-FRCAB6  
About • paper received ※ 23 June 2019       paper accepted ※ 01 July 2019       issue date ※ 14 August 2019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)