J-PARC charge exchange experiment with picosecond pulse train laser system

Fuchi, Aoi*; Harada, Hiroyuki  ; Yoneda, Hitoki*; Michine, Yurina*; Saha, P. K.   ; Yoshimoto, Masahiro  ; Kinsho, Michikazu  ; Shibata, Takanori*

At the J-PARC, a non-destructive method of "laser charge exchange injection" has been proposed and is under development to replace the carbon foil. In addition, the development of a non-destructive beam profile monitor is also important to stabilize the beam operation. In this study, we developed a laser source and a multi-pass cavity for this purpose, and performed the second experiment. In the development of the laser source, the timing of each of the five laser amplifiers was staggered, and we succeeded in producing a laser with a flat pulse structure. In the development of the multi-pass cavity, we succeeded in focusing 16 pulses of laser simultaneously to the irradiation point. As a result, a charge exchange efficiency of 16.8%, 30 times higher than the previous efficiency of 0.57%, was achieved. In this presentation, we report the results of the laser source development and the multi-pass cavity development.