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TY - CONF AU - Ohmi, K. AU - Flanagan, J.W. AU - Fukuma, H. AU - Ikeda, H. AU - Mulyani, E. AU - Shibata, K. AU - Suetsugu, Y. AU - Tobiyama, M. ED - Schaa, Volker RW ED - Arduini, Gianluigi ED - Pranke, Juliana ED - Seidel, Mike ED - Lindroos, Mats TI - Electron Cloud Instability in SuperKEKB Phase I Commissioning J2 - Proc. of IPAC2017, Copenhagen, Denmark, 14â19 May, 2017 C1 - Copenhagen, Denmark T2 - International Particle Accelerator Conference T3 - 8 LA - english AB - 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. PB - JACoW CP - Geneva, Switzerland SP - 3104 EP - 3106 KW - electron KW - target KW - simulation KW - permanent-magnet KW - solenoid DA - 2017/05 PY - 2017 SN - 978-3-95450-182-3 DO - 10.18429/JACoW-IPAC2017-WEPIK075 UR - http://jacow.org/ipac2017/papers/wepik075.pdf ER -