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 - Toyama, T. AU - Kobayashi, A. AU - Nakamura, T. AU - Okada, M. AU - Shobuda, Y. AU - Tobiyama, M. ED - Gianfelice, Eliana ED - Nagaitsev, Sergei ED - Kim, Dong Eon ED - Marx, Michaela ED - Schaa, Volker R. W. TI - Beam Instability Issue and Transverse Feedback System in the MR of J-PARC J2 - Proc. of HB2021, Batavia, IL, USA, 04-08 October 2021 CY - Batavia, IL, USA T2 - ICFA ABDW on High-Intensity and High-Brightness Hadron Beams T3 - 64 LA - english AB - In the J-PARC MR, according to the beam power upgrade over 100 kW, beam losses due to transverse collective beam instabilities had started to appear. We had introduced "bunch-by-bunch feedback" system in 2010. Continuing beam power upgrade over 250 kW again caused the transverse instabilities. We introduced "intra-bunch feedback" system in 2014. This has been suppressing those instabilities very effectively. But further beam power upgrade over 500 kW (2.6·10⁺¹⁴ ppp, 8 bunches) needs upgrade of "intra-bunch feedback" system. The current understanding of the transverse instabilities in the MR and the effect of the feedback system are presented from the view points of simplified simulation without the space charge effect and measurements. We are upgrading the system in two steps. The first step is "time-interleaved sampling and kicking" with two feedback systems. The second step is getting the sampling rate twice as much as the current rate, ~110 MHz. Details are explained using simulation. PB - JACoW Publishing CP - Geneva, Switzerland SP - 208 EP - 213 KW - feedback KW - simulation KW - timing KW - extraction KW - operation DA - 2022/04 PY - 2022 SN - 2673-5571 SN - 978-3-95450-225-7 DO - doi:10.18429/JACoW-HB2021-THAC1 UR - https://jacow.org/hb2021/papers/thac1.pdf ER -