Laser acceleration for stable electron beams at JAEA-APRC

Kotaki, Hideyuki; Kando, Masaki; Daito, Izuru; Hayashi, Yukio; Kawase, Keigo; Kameshima, Takashi*; Chen, L. M.*; Fukuda, Yuji; Homma, Takayuki; Esirkepov, T. Z.; Koga, J. K.; Pirozhkov, A. S.; Faenov, A. Y.; Pikuz, T.*; Kiriyama, Hiromitsu; Okada, Hajime; Kondo, Shuji; Kanazawa, Shuhei; Shimomura, Takuya; Nakai, Yoshiki; Tanoue, Manabu*; Akutsu, Atsushi; Sasao, Hajime; Wakai, Daisuke*; Motomura, Tomohiro*; Daido, Hiroyuki; Bulanov, S. V.

Laser Wake Field Acceleration (LWFA) is now regarded as a basis for the next-generation of charged particle accelerators. In order to generate a stable high-quality electron beam for applications, we conduct laser acceleration experiments by self-injection and optical injection. The laser contrast ratio is one of the important parameters for LWFA due to pre-plasma effects. In the self-injection experiment we study a laser contrast effect to the laser accelerated electron beam. For the high laser contrast ratio, a 140MeV monoenergetic electron beam with a charge of 100 pC is obtained. For the low laser contrast ratio, a low quality electron beam or no electron beam is generated due to pre-plasma. Optical injection by collision of two laser pulses has been proposed as a stable and controllable injection. A monoenergetic 134 MeV electron beam with a charge of 100 pC is generated by the optical injection in a head-on laser pulses configuration.