Author: Ikeda, H.
Paper Title Page
WEPIK075 Electron Cloud Instability in SuperKEKB Phase I Commissioning 3104
 
  • K. Ohmi, J.W. Flanagan, H. Fukuma, H. Ikeda, E. Mulyani, K. Shibata, Y. Suetsugu, M. Tobiyama
    KEK, Ibaraki, Japan
 
  Beam size blow-up due to electron cloud has been observed in Phase I commissioning of SuperKEKB. Vacuum chambers in LER (low energy positron ring) were cured by antechamber and TiN coating for electron cloud. Some parts, bellows, were not cured by the coating. In the early stage of Phase I commissioning, beam size blow up has been observed above a threshold current. The blow up was suppressed by weak permanent magnets generating longitudinal field, which cover the bellows. Electron cloud current have been monitored during the commissioning. The thresholds for the electron cloud induced fast head-tail instability have been simulated in the operating beam conditions. Coupled bunch instability caused by electron cloud has been measured in the operating beam conditions and installation of the permanent magnets. The measurement and simulation results are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK075  
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