@misc{oai:repo.qst.go.jp:00071854,
 author = {Mizushima, Kota and Furukawa, Takuji and Sato, Shinji and Hara, Yousuke and Saotome, Naoya and Saraya, Yuichi and Tansho, Ryohei and Shirai, Toshiyuki and Noda, Koji and 水島 康太 and 古川 卓司 and 佐藤 眞二 and 原 洋介 and 早乙女 直也 and 皿谷 有一 and 丹正 亮平 and 白井 敏之 and 野田 耕司},
 month = {Nov},
 note = {The carbon-ion beam is slowly extracted from the Heavy Ion Medical Accelerator in Chiba (HIMAC) synchrotron using the third-order resonance with the RF-knockout method for scanned carbon-ion therapy. However, an overshoot of the beam spill at the start of extraction is often induced by a slight variation of the beam emittance in operation cycles. It brings dose hot spot inside the target volume, because the tolerable beam-intensity is typically low in scanning irradiation. We have added short extraction, called preliminary extraction, before irradiation in order to remove the uncontrollable spilled particles. During preliminary extraction, it is necessary to prevent the beam delivering to the patient. Therefore, a fast beam shutter on which an ionization chamber is mounted was developed, and it was installed in the extraction line. The fast shutter enables us to switch from preliminary extraction to irradiation within 100 ms, and the reliability of the beam-intensity control system was drastically improved by the preliminary extraction technique., 19th International conference on accelerators and beam utilizations (ICABU2015)},
 title = {Reliable Intensity Control System Using a Fast Beam Shutter at HIMAC},
 year = {2015}
}