@misc{oai:repo.qst.go.jp:00075622,
 author = {黄, 開 and Neagu, Liviu and Nakamiya, Yoshihide and Rotaru, Florin and Secareanu, Radu and Cuciuc, Mihai and Matei, Dan and Pirozhkov, Alexander and Bierwage, Andreas and Ogura, Koichi and Sagisaka, Akito and Nakanii, Nobuhiko and Kiriyama, Hiromitsu and 神門, 正城 and HUANG, KAI and Pirozhkov, Alexander and Bierwage, Andreas and Ogura, Koichi and Sagisaka, Akito and Nakanii, Nobuhiko and Kiriyama, Hiromitsu and Kando, Masaki},
 month = {Apr},
 note = {Laser wakefield acceleration  (LWFA) [1] has been studied intensively in the past decades. With the optimization of chirped pulse amplification technology (CPA) [2], high quality electron beams with energies over GeV [3] have been generated. The ultrahigh acceleration gradient allows for the construction of a table top x-ray free electron laser [4]. To achieve lasing in the x-ray wavelength range, GeV class electron beam with high brightness is necessary.
We succeeded generating highly collimated quasi-monoenergetic electron beams with peak energies up to GeV via ionization-injection [5, 6] using the J-KAREN-P laser. By incident of 300 TW laser pulses into a 10 mm gas jet, comparison studies were performed with pure (He), (He:Ne) mixture and (He:N2) mixture gases. We observed that the divergences, energies and charges of electron beams have dependences on gas species and mixture ratios. The smallest divergence of electron beams from (He:Ne) was merely 0.18 mrad (rms), which was 5 times smaller than that from (He:N2) gas. For many shots, we got extremely high charge electron bunches at plasma denties lower than the self-injection threshold. This study shows the capabilities of the ionization injection regime manipulate and optimize the qualities of the GeV class electron beams from laser wakefield acceleration., HEDS2019},
 title = {Highly collimated high charge GeV electron beam from laser wakefield acceleration via ionization injection},
 year = {2019}
}