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TY - CONF AU - Shibata, K. AU - Hisamatsu, H. AU - Ishibashi, T. AU - Kanazawa, K. AU - Shirai, M. AU - Suetsugu, Y. AU - Terui, S. ED - Li, Ying-ying ED - Li, Lu ED - Schaa, Volker RW TI - Commissioning Status of SuperKEKB Vacuum System J2 - Proc. of eeFACT2018, Hong Kong, China, 24-27 September 2018 CY - Hong Kong, China T2 - ICFA ABDW on High Luminosity Circular e$^+$e$^-$ Colliders T3 - 62 LA - english AB - In the upgrade from the KEKB to the SuperKEKB, approximately 93% and 20% of the beam pipes and vacuum components of the positron ring and the electron ring were replaced with new ones. In the Phase-1 commissioning in 2016, vacuum scrubbing and confirmation of the stabilities of new vacuum components at approximately 1 A were carried out. Though some problems such as pressure bursts accompanying beam losses were revealed, no serious problem was found in the vacuum system. During the subsequent shutdown, the countermeasures against the problems were taken, and new beam pipes and components such as beam collimators were installed. The Phase-2 commissioning, where beam collision tuning was mainly performed, was carried out from March to July 2018. The collimators worked very well to suppress the background noise of the Belle-II detector, though some of them were damaged by the beam. The frequency of the pressure burst drastically decreased though the typical beam currents were lower than those of the Phase-1. The vacuum system of the SuperKEKB has been working generally well so far. The total beam doses of the SuperKEKB exceeded 1000 Ah, and the pressures decreased as expected. PB - JACoW Publishing CP - Geneva, Switzerland SP - 226 EP - 233 KW - vacuum KW - MMI KW - photon KW - wiggler KW - detector DA - 2019/04 PY - 2019 SN - 978-3-95450-216-5 DO - DOI: 10.18429/JACoW-eeFACT2018-WEOAB01 UR - http://jacow.org/eefact2018/papers/weoab01.pdf ER -