JACoW is a publisher in Geneva, Switzerland that publishes the proceedings of accelerator conferences held around the world by an international collaboration of editors.
TY - CONF AU - Terui, S. AU - Fukuma, H. AU - Funakoshi, Y. AU - Ishibashi, T. AU - Nakamura, T. AU - Ohmi, K. AU - Ohnishi, Y. AU - Tobiyama, M. AU - Ueki, R. ED - Zimmermann, Frank ED - Tanaka, Hitoshi ED - Sudmuang, Porntip ED - Klysubun, Prapong ED - Sunwong, Prapaiwan ED - Chanwattana, Thakonwat ED - Petit-Jean-Genaz, Christine ED - Schaa, Volker R.W. TI - The Report of Machine Studies Related to the Vertical Beam Size Blow-Up in SuperKEKB LER J2 - Proc. of IPAC2022, Bangkok, Thailand, 12-17 June 2022 CY - Bangkok, Thailand T2 - International Particle Accelerator Conference T3 - 13 LA - english AB - In the Low Energy Ring (LER) for positrons in the SuperKEKB, a vertical beam size blow-up was observed when the bunch current was approximately 1 mA. If a beam size blow-up occurs, the design luminosity cannot be achieved. Therefore, beam size blow-ups must be pre-vented. According to calculations, the bunch current threshold of the Transverse Mode Coupling instability (TMCI) is 2 mA or more, and the observed value is 50% or smaller. This vertical beam size blow-up cannot be explained by ordinary TMCI. This paper shows that by analyzing factors such as beam oscillation, the cause of the vertical beam size blow-up was determined. The study results showed that the vertical beam size blow-up in the LER was caused by the oscillations of the -1 mode. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2169 EP - 2172 KW - experiment KW - emittance KW - luminosity KW - beam-beam-effects KW - coupling DA - 2022/07 PY - 2022 SN - 2673-5490 SN - 978-3-95450-227-1 DO - doi:10.18429/JACoW-IPAC2022-WEPOTK050 UR - https://jacow.org/ipac2022/papers/wepotk050.pdf ER -