Development of hybrid type carbon stripper foils with high durability at >1800K for RCS of J-PARC

The Japan-Proton Accelerator Research Complexes (J-PARC) requires thick carbon stripper foils (200-300 mug/cm²) to strip electrons from the H^- beam supplied by the linac before injection into the RCS of J-PARC. High-intensity H^- beam and circulating bunched beam give much energy depositions to conventional carbon stripper foils. Thus carbon stripper foils with high durability at 1800 K are urgent and indispensable for this accelerator. Recently, we have developed hybrid type boron mixed carbon stripper foils (HBC-foil). Namely, the lifetime measurement of the foils was tested by using a 3.2 MeV, Ne⁺ DC beams of 2.5 muA, in which a significant amount of energy was deposited in the foils. We have investigated double- layered effects on the lifetime of the HBC-foils. The maximum lifetime was found to be extremely long , 30- and 250-times longer than those of diamond and commercially available best carbon foils (CM-foil). It was also found that the foils show free from shrinkage, and an extremely low thickness reduction rate even at a high temperature of 1800 K. In this poster the foil preparation procedure and lifetime measurements with a 3.2 MeV Ne⁺ beam is reported.