3 MeV beam scrapers for the J-PARC Linac

Hirano, Koichiro  ; Sugimura, Takashi*; Kurihara, Toshikazu*

Beam scrapers made of carbon composite have been used in the MEBT1 of the J-PARC Linac. We could use a beam scraper without a problem for five months when the scraper received to 1.3 times as high as a normal average beam current of the scraper in 1MW beam operation. In order to evaluate the limits of the beam scraper, we conducted the scraper irradiation test by using an off-line 3 MeV beam test-stand. We measured the surface temperature by a high-speed radiation thermometer which can be measured the maximum temperature of 3500C. As the result of the test, we observed the gasification of carbon became significant when the surface temperature exceeded 2900C. To avoid significant thermal decomposition of the scraper, we need to keep the maximum temperature less than 2900C. This paper describes present status of the 3 MeV beam scraper and results of the beam irradiation test. This paper describes beam irradiation test of the 3 MeV beam scraper and scraper materials.