Quantitative monitoring of the stripper foil degradation in the 3-GeV rapid cycling synchrotron of the Japan proton accelerator research complex

Saha, P. K.   ; Yoshimoto, Masahiro  ; Yamazaki, Yoshio ; Hotchi, Hideaki  ; Harada, Hiroyuki  ; Hayashi, Naoki  ; Yamamoto, Kazami   ; Kinsho, Michikazu  ; Irie, Yoshiro*

The 3-GeV RCS of the J-PARC requires a long lifetime stripper foil in order to ensure a stable operation. A sudden failure of the foil breaks the accelerator availability as well as raised maintenance issues. A foil degradation (such as foil thinning, pinhole formation) could be a signal of the foil breaking. An efficient monitoring system is needed in order to determine a proper lifetime of a foil for the RCS 1 MW operation so as to avoid any sudden foil failure. During the past 4 months operation of the RCS with about 200 kW beam power to the MLF and nearly 300 kW equivalent beam power to the MR, a single foil was used but there was no observable degradation so far.