Development of beam scrapers using a 3-Mev linac at J-PARC

Hirano, Koichiro  ; Asano, Hiroyuki; Ishiyama, Tatsuya; Ito, Takashi  ; Okoshi, Kiyonori ; Oguri, Hidetomo  ; Kondo, Yasuhiro   ; Kawane, Yusuke; Kikuzawa, Nobuhiro ; Sato, Yoshikatsu; Shinozaki, Shinichi ; Shinto, Katsuhiro   ; Takei, Hayanori   ; Chishiro, Etsuji; Nemoto, Yasuo; Miura, Akihiko ; Mizobata, Satoshi; Meigo, Shinichiro   ; Morishita, Takatoshi  ; Kurihara, Toshikazu*; Shibata, Takanori*; Sugimura, Takashi*; Takagi, Akira*; Nammo, Kesao*; Fukui, Yuji*; Futatsukawa, Kenta*; Fang, Z.*; Maruta, Tomofumi*; Miyao, Tomoaki*; Hori, Toshihiko*; Sawabe, Yuki*; Mayama, Minoru*

We have used a beam scraper with the incident angle of 65deg to reduce the beam power deposition density in the MEBT between a 324 MHz RFQ and a 50-MeV DTL of the J-PARC linac. The 65 scraper was irradiated by the H beam up to particle number of 1.47E22. We observed a lot of surface projections with several hundred micrometers high in the beam irradiation damage on the scraper by using the laser microscope. In order to study the limits of scrapers, we constructed a new 3 MeV linac at J-PARC. We will conduct the scraper irradiation test at the end of this year.