Complementary characterization of radioactivity produced by repetitive laser-driven proton beam using shot-to-shot proton spectral measurement and direct activation measurement

Ogura, Koichi; Shizuma, Toshiyuki; Hayakawa, Takehito; Yogo, Akifumi; Nishiuchi, Mamiko; Orimo, Satoshi; Sagisaka, Akito; Pirozhkov, A. S.; Mori, Michiaki; Kiriyama, Hiromitsu; Kanazawa, Shuhei; Kondo, Shuji; Nakai, Yoshiki*; Shimomura, Takuya; Tanoue, Manabu*; Sasao, Hajime*; Wakai, Daisuke*; Sasao, Fumitaka; Okada, Hajime; Kimura, Toyoaki*; Oishi, Yuji*; Nayuki, Takuya*; Fujii, Takashi*; Nemoto, Koshichi*; Daido, Hiroyuki

A proton beam driven by a repetitive high-intensity-laser is utilized to induce a Li(p,n)Be nuclear reaction. The total activity of Be are evaluated by two different methods. The activity obtained measuring the decay -rays after 1912 shots at 1 Hz is 1.70.2 Bq. This is in good agreement with 1.60.3 Bq evaluated from the proton energy distribution measured using a time-of-flight detector and the nuclear reaction cross-sections. We conclude that the production of activity can be monitored in real time using the time-of-flight-detector placed inside a diverging proton beam coupled with a high-speed signal processing system.