First step analysis of hybrid type boron-doped carbon stripper foils for RCS of J-PARC

Yamazaki, Yoshio ; Yoshimoto, Masahiro  ; Takeda, Osamu; Kinsho, Michikazu  ; Sugai, Isao*

J-PARC requires thick carbon stripper foils to strip electrons from the H beam supplied by the linac before injection into the Rapid Cycling Synchrotron (RCS). Foil thickness is about 200 g/cm corresponding to conversion efficiency of 99.7% from the primary H beams of 181 MeV energy to H. For this purpose, we have successfully developed hybrid type thick boron-doped carbon (HBC) stripper foils, which showed a drastic improvement not only with respect to the lifetime, but also with respect to thickness reduction and shrinkage at high temperature during long beam irradiation. We started to study carbon stripper foils microscopically why carbon foils have considerable endurance for the beam impact by boron-doped. At first, we made a comparison between nominal carbon and HBC by the electric microscope and ion-induced analysis.