First measurement and online monitoring of the stripper foil thinning and pinhole formation to achieve a longer foil lifetime in high-intensity accelerators

大強度加速器において荷電変換膜の長期間使用を達成するために必要な膜厚減少やピンホール発生のオンラインモニタリングと世界初の測定結果

Saha, P. K.   ; 吉本 政弘  ; 畠山 衆一郎; 發知 英明  ; 原田 寛之  ; 田村 文彦   ; 山本 風海   ; 山崎 良雄 ; 金正 倫計  ; 入江 吉郎*

Saha, P. K.; Yoshimoto, Masahiro; Hatakeyama, Shuichiro; Hotchi, Hideaki; Harada, Hiroyuki; Tamura, Fumihiko; Yamamoto, Kazami; Yamazaki, Yoshio; Kinsho, Michikazu; Irie, Yoshiro*

We have established and implemented a nondestructive online monitoring system for the first time for measuring stripper foil thinning and pinhole formation, which are believed to the foil breaking signals caused by high-intensity beam irradiation. A longer foil lifetime is desired, while a foil failure during operation not only reduces the accelerator availability but also has serious issues for regular accelerator maintenances. The present research has been carried out at the RCS of J-PARC, where we aimed to ensure proper uses of foil and to achieve a longer foil lifetime without any failure. We have precisely measured a foil thinning and pinhole outbreak information to obtain a detail of foil degradation to determine a realistic foil lifetime by achieving a record of nearly 2 years of operation with a single foil and without any failures.