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Mikami, Katsuhiro; Hasegawa, Noboru; Okada, Hajime; Kondo, Shuji; Kawachi, Tetsuya
no journal, ,
An outdoor-use laser system to improve the performances of existing tunnel inspection techniques is studied. One of the typical concepts is that the blow by hammer in routine hammering test is replaced by the laser pulse irradiation. This new laser system is required to provide high average output power (5 J, 50 Hz, 
15 ns) with a compact geometry enough to mount on the inspection vehicle (4.2 m 
0.8 m). Dramatic speed-up of the inspection is expected by the combination of this new laser system and a laser scanning frequency measurement system.
Mikami, Katsuhiro; Hasegawa, Noboru; Okada, Hajime; Kondo, Shuji; Kawachi, Tetsuya
no journal, ,
An outside-use laser system to improve the performances of existing tunnel inspection techniques is studied. One of the typical concepts is that the blow by hammer in routine test is replaced by the laser pulse irradiation. This new laser system is required to provide high average output power (5 J, 50 Hz, 15 ns) with a small-scale geometry enough to mount on the inspection vehicle (4.2 m 0.8 m). In this presentation, we will report a potential to demonstrate 5 J output.
Mikami, Katsuhiro; Hasegawa, Noboru; Okada, Hajime; Kondo, Shuji; Kawachi, Tetsuya
no journal, ,
An outdoor-use laser system to improve the performances of existing tunnel inspection techniques is studied. One of the typical concepts is that the blow by hammer in routine hammering test is replaced by the laser pulse irradiation. This new laser system is required to provide high average output power (5 J, 50 Hz, 15 ns) with a compact geometry enough to mount on the inspection vehicle (4.2 m 0.8 m). Dramatic speed-up of the inspection is expected by the combination of this new laser system and a laser scanning frequency measurement system.
Fuchi, Aoi*; Harada, Hiroyuki; Yoneda, Hitoki*; Michine, Yurina*; Saha, P. K.; Yoshimoto, Masahiro; Kinsho, Michikazu; Shibata, Takanori*
no journal, ,
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.
Fuchi, Aoi*; Harada, Hiroyuki; Yoneda, Hitoki*; Michine, Yurina*; Saha, P. K.; Yoshimoto, Masahiro; Kinsho, Michikazu; Shibata, Takanori*
no journal, ,
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.