@article{oai:repo.qst.go.jp:00046298,
 author = {Katagiri, Ken and Furukawa, Takuji and Mizushima, Kota and Uchiyama, Hiroshi and Takeshita, Eri and Himukai, Takeshi and Satou, Shinji and Iwata, Yoshiyuki and Shirai, Toshiyuki and Noda, Kouji and 片桐 健 and 古川 卓司 and 水島 康太 and 竹下 英里 and 日向 猛 and 佐藤 眞二 and 岩田 佳之 and 白井 敏之 and 野田 耕司},
 issue = {24},
 journal = {Nuclear Instruments & Methods in Physics Research Section B},
 month = {Apr},
 note = {In order to realize a precise dose distribution in heavy-ion cancer therapy, high beam stability is required for the accelerator complex. Owing to load fluctuation caused by the upper ring, which is one of the two rings in HIMAC, current dips of 5-10 Hz were observed in the power supply for the bending/quadrupole magnet of the other lower ring. The parameters of the beam stability, such as the spill variation, the beam position, and the size, were adversely affected by the current dips. In order to suppress these current dips, we developed a new feed-forward system in the magnet power supply. We verified the performance of the feed-forward system by measuring the suppression of the current dips. We also performed beam
experiments to measure the variation of the horizontal tune and the structure of the beam spill, which is slowly extracted by the resonance method. The experimental result showed that the current dips were successfully reduced by the system to DI/I =1E-6. It was also confirmed that the horizontal tune and the spill structure could be stabilized by the current dip suppression.},
 pages = {2905--2910},
 title = {Beam stability improvement of the HIMAC synchrotron using a feed-forward system for magnet power supplies},
 volume = {269},
 year = {2011}
}