Long pulse arc-driven proton source for high intensity linac of iBNCT

iBNCT大強度リニアックのための長パルスアーク放電式陽子イオン源

柴田 崇統*; 杉村 高志*; 池上 清*; 高木 昭*; 佐藤 将春*; 内藤 富士雄*; 大越 清紀 ; 長谷川 和男

Shibata, Takanori*; Sugimura, Takashi*; Ikegami, Kiyoshi*; Takagi, Akira*; Sato, Masaharu*; Naito, Fujio*; Okoshi, Kiyonori; Hasegawa, Kazuo

As preparations for non-clinical studies in Ibaraki Boron Neutron Capture Therapy (iBNCT), physics and cell experiments have been started in 2018 by producing high intensity proton beam in the linac with beam energy up to 8 MeV and average current up to 2 mA. In order to satisfy original clinical trial conditions, higher beam intensity upgrade is required to obtain average 5 mA beam current with enough stability. For this purpose, an arc-driven proton source equipped with lanthanum hexaboride (LaB) filament is under development. A peak beam current of 53 mA is obtained in the off-line test-stand, which is equivalent to average 5 mA in the actual operation with beam pulse up to 1 ms and repetition up to 100 Hz. Generally, arc pulser power supply (PS) should be large size to satisfy high and stable arc voltage/current, while the space-saving is important for the medical application. In the present study, a new arc pulser PS is developed for these requirements. In the presentation, the arc pulser PS and brief status of the proton source development is reported.