WEOI04 　ビーム診断・ビーム制御①　 7月31日 国際科学イノベーション棟5階 ホール 16:40-17:00

カーボン素材を用いた大強度3 MeV H-ビーム用バンチシェイプモニター

Bunch shape monitor for the high-intensity H- beam with 3 MeV using the carbon material

○北村 遼（JAEA），二ツ川 健太（KEK），林 直樹，平野 耕一郎（JAEA），小坂 知史（Nippon Advanced Technology Co., Ltd.），宮尾 智章（KEK），守屋 克洋（JAEA），根本 康雄（Nippon Advanced Technology Co., Ltd.），小栗 英知（JAEA）

○Ryo Kitamura (JAEA), Kenta Futatsukawa (KEK), Naoki Hayashi, Kouichirou Hirano (JAEA), Satoshi Kosaka (Nippon Advanced Technology Co., Ltd.), Tomoaki Miyao (KEK), Katsuhiro Moriya (JAEA), Yasuo Nemoto (Nippon Advanced Technology Co., Ltd.), Hidetomo Oguri (JAEA)

The longitudinal measurement and tuning at the beam transport after the RFQ are important to reduce the beam loss and the emittance growth in the J-PARC linac, when the high-intensity H- beam of more than 60 mA is supplied. The new bunch shape monitor (BSM) using the carbon-nanotube (CNT) wire is necessary to measure the bunch shape of the high-intensity H- beam with 3 MeV, because the CNT wire has a high-temperature tolerance and a small energy deposit due to the low density. However, when the high voltage was applied to the CNT wire to extract the secondary electron derived from the H- beam, the discharge prevents the power supply from applying the voltage. Therefore, the discharge should be suppressed to measure the bunch shape with stability. In order to suppress the discharge, the vacuum chamber was evacuated to around 10-7 Pa and the sources of the creeping discharge were removed. Considering the characteristics of the CNT as the emitter, when the length of the CNT wire was short, the leak current was reduced and the high voltage of -10 kV was applied to the CNT wire. The current status and future prospects of the BSM using the CNT wire are reported in this presentation.