Generation of sub-MeV class quasi-monoenergetic electron bunch driven by 3-TW laser and gas interactions

Mori, Michiaki; Kotaki, Hideyuki; Hayashi, Yukio; Kando, Masaki; Bulanov, S. V.; Ogura, Koichi; Pirozhkov, A. S.; Kondo, Kiminori; Nishimura, Hiroaki*; Sugiyama, Akira

Density-ramp injection is one of methods to generate high quality sub-MeV class electron bunch. From LBL group, the transverse energy spread of p/p=0.026 was obtained at 400 keV class quasi-monoenergetic electron bunches driven by 10-TW laser and short-focus optical configuration. In particular, since long-focus configuration provides lower electric field gradient in the transverse direction, and it can be generate low transverse energy spreaded electron bunch. In this work, we studied on sub-MeV class electron bunch generation driven by 3-TW laser and long-focus configuration. We obtained transverse momentum spread of p/p=0.016 at 200 keV at 200 keV class quasi-monoenergetic electron bunches. This experimental result reveals momentum spread in the transverse direction is suppressed by the long-focus configurations.