Efficient production of a collimated MeV proton beam from a Polyimide target driven by an intense femtosecond laser pulse
Nishiuchi, Mamiko; Daido, Hiroyuki; Yogo, Akifumi; Orimo, Satoshi; Ogura, Koichi; Ma, J.-L.; Sagisaka, Akito; Mori, Michiaki; Pirozhkov, A. S.; Kiriyama, Hiromitsu; Bulanov, S. V.; Esirkepov, T. Z.; Choi, I. W.*; Kim, C. M.*; Jeong, T. M.*; Yu, T. J.*; Sung, J. H.*; Lee, S. K.*; Hafz, N.*; Pae, K. H.*; Noh, Y.-C.*; Ko, D.-K.*; Lee, J.*; Oishi, Yuji*; Nemoto, Koshichi*; Nagatomo, Hideo*; Nagai, Keiji*; Azuma, Hirozumi*
High-flux energetic protons whose maximum energies are up to 4 MeV are generated by an intense femtosecond Titanium Sapphire laser pulse interacting with a 7.5, 12.5, and 25
m thick Polyimide tape targets. The laser pulse energy is 1.7 J, duration is 34 fs, and intensity is 3
10
Wcm
. The amplified spontaneous emission (ASE) has the intensity contrast ratio of 4
10
. The conversion efficiency from laser energy into proton kinetic energies of
3% is achieved, which is comparable or even higher than those achieved in the previous works with nanometer-thick targets and the ultrahigh contrast laser pulses (
10
).