TEMPERATURE MEASUREMENTS OF CARBON STRIPPER FOIL BY PULESD 650KEV H- ION BEAM*.

Thick carbon foils (>300 mg/cm2)has been used for stripping of H- ion beam into protons at the injection stage of the 3GeV Rapid Cycling Synchrotron (3GeV-RCS) in J-PARC. The carbon stripper foils with high durability at high temperature>1800 ºK are strongly required. A new irradiation system for foils is in progress using the KEK 650keV Cockcroft-Walton accelerator which can simulate the high-energy deposition upon foils in the RCS. The most important factor that affects the foil lifetime is the foil temperature. We are developing the measuring method of the temperature using a photo-transistor when a foil is irradiated by the short pulses with several tens ~ several hundreds microsecond durations. Preliminary results are described in this report