Improvement of the JAEA J-KAREN laser and its applications to high field science, 4; Phase rotation technique of the intense and short pulse laser driven proton beam by synchronous RF field

Nishiuchi, Mamiko; Daido, Hiroyuki; Yogo, Akifumi; Mori, Michiaki; Kiriyama, Hiromitsu; Kanazawa, Shuhei; Sagisaka, Akito; Ogura, Koichi; Orimo, Satoshi; Kondo, Shuji; Yamamoto, Yoichi ; Shimomura, Takuya*; Tanoue, Manabu*; Nakai, Yoshiki; Akutsu, Atsushi; Bulanov, S. V.; Kimura, Toyoaki; Tajima, Toshiki; Ikegami, Masahiro*; Nakamura, Shu*; Iwashita, Yoshihisa*; Shirai, Toshiyuki*; Soda, Hikaru*; Tajima, Yujiro*; Noda, Akira*; Oishi, Yuji*; Nemoto, Koshichi*

By applying the RF filed to the high intensity short pulse laser-driven MeV proton beam, we have demonstrated the generation of the quasi-monoenegetic proton spectra and modification of the spatial distribution of proton beams. We used J-KAREN laser system at the JAEA. We focused it to Polyimide target. The intensity was 410Wcm. We produced repetetively the proton beams with the maximum energy of 2.2 MeV. We guided this proton beam to the cabvity of the RF field. We observed significant energy peaks in the proton energy spectra. The resultant energy concentration was 11 % (FWHM) out of 100 %. At the same time, we could change the divergence of the beam with the RF field. According to the Monte-Carlo simulation, the spatially converging proton beam has energy spectra with the energy spread of 100 %, on the contrary the spatially diverging beam has mono-energetic energy spectra. This method is very useful because it can apply to repetitivelly produced proton beams to control the energy as well as spatial distributions.