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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.
cluster targetsMatsui, Ryutaro; Fukuda, Yuji; Kawahito, Daiki*; Kishimoto, Yasuaki*
no journal, ,
In order to examine energy distributions of ions, we performed a 3D PIC simulation concerning an interaction between the high power laser and H cluster targets with a radius of 600 nm, at a laser intensity of 1.010
W/cm
. The simulation results shows that in addition to symmetric electric fields by the Coulomb repulsive force, asymmetric sheath electric fields are generated due to electrons pushed forward by the Lorenz force, JB. As a result, ions are accelerated forward up to 100 MeV by the anisotropic electric field of Coulomb explosion which consists of the symmetric electric fields and the asymmetric sheath fields. These results suggest that by using J-KAREN-P laser and submicron-size H cluster targets, protons with energies of 100 MeV can be produced.
Nishikino, Masaharu; Hasegawa, Noboru; Kawachi, Tetsuya; Suemoto, Toru*; Onishi, Naofumi*; Ito, Atsushi*; Inogamov, N.*; Faenov, A. Y.*
no journal, ,
no abstracts in English
Daido, Hiroyuki
no journal, ,
no abstracts in English
Kado, Masataka; Kishimoto, Maki; Tamotsu, Satoshi*; Yasuda, Keiko*; Aoyama, Masato*; Tone, Shigenobu*; Shinohara, Kunio*
no journal, ,
A laser-plasma soft X-ray microscope which is combination of a highly intense laser-plasma soft X-ray source and contact microscopy has been developed. We have proposed a correlative microscopy with the laser-plasma soft X-ray microscope and a fluorescent microscope that is to observe the same biological cells with the both microscopes at the same time. Live hydrated biological cells and various cellular organelles of them have been observed with the correlative microscopy. Using the information of the cellular organelles obtained with the fluorescence microscope, inner structures obtained with the soft X-ray microscope are exactly identified. Since the spatial resolution of the soft X-ray microscope is much higher than that of the fluorescent microscope, fine structures of the cellular organelles of the live biological cells have been visualized with the correlative microscopy.
Mori, Michiaki; Kiriyama, Hiromitsu; Miyasaka, Yasuhiro; Kishimoto, Maki; Kotaki, Hideyuki; Hayashi, Yukio; Kando, Masaki; Kondo, Kiminori
no journal, ,
Improvement of controllability and stability at laser-driven particle beams are important for multi-purpose applications. Improvement of the laser stability is important to improvement such parameters. Especially, compensation of higher order dispersion at a CPA laser system influences stability of laser temporal profile. In this work, we demonstrate new concept of higher order dispersion management by using assist pulse compression. We confirmed 1e-7 prepulse level at sub-ns region and 120 dB/ps slew rate at sub-ps region.
Hayakawa, Takehito
no journal, ,
For study of nuclear science various quantum beams like ions, neutrons, electrons, 
-rays have been developed using accelerators. Progress of high peak power laser has provided us a new type radiation source based on laser plasma interactions. These laser-based quantum beams have excellent features of short-pulse, high brightness, and continues energy distribution. They opens a new fields in nuclear science.
Miyasaka, Yasuhiro; Kiriyama, Hiromitsu; Kishimoto, Maki; Mori, Michiaki; Kando, Masaki; Kondo, Kiminori
no journal, ,
We are developing an optically synchronized low-jitter pump source for stable optical parametric chirped-pulse amplification. Spectrum of laser pulses provided by Ti:Sapphire laser oscillator is expanded to 1064 nm with photonic crystal fiber (PCF). We successfully stabilize fluctuation of PCF-output spectrum in less than 0.1% by feedback control of laser polarization of input pulses. The stabilization provide us with power stability less than 1% after fiber amplification.
Kiriyama, Hiromitsu; Mori, Michiaki; Pirozhkov, A. S.; Ogura, Koichi; Nishiuchi, Mamiko; Kando, Masaki; Sakaki, Hironao; Kishimoto, Maki; Miyasaka, Yasuhiro; Kon, Akira; et al.
no journal, ,
We report on recent progress on the J-KAREN laser upgrade to realize 10 W/cm intensity at 0.1 Hz. Our current high-spatiotemporal-quality broadband pulse from the front end is amplified in the final amplifier to over 55 J. We plan to mention the future prospects. We also introduce ultra-high intensity lasers worldwide.
Sekiguchi, Kentaro; Jinno, Satoshi*; Tanaka, Hirotaka*; Ichinose, Kosuke*; Kanasaki, Masato*; Sakaki, Hironao; Kondo, Kiminori; Matsui, Ryutaro; Kishimoto, Yasuaki; Fukuda, Yuji
no journal, ,
The size of clusters, produced in an expansion of supercooled, high pressure molecular hydrogen gas into vacuum, has been evaluated by measuring the angular distribution of scattered light. The data are analyzed based on the Mie scattering theory. Here obtaining the size distribution of clusters reduces to solving the inverse problem. Since the scattering coefficient is a matrix, it is necessary to determine the inverse matrix. However, if you solve this equation straightforward, the size distribution often oscillates to the negative values and becomes the discrete distribution by external factors such as noise included in the measurement results. Therefore, we have built an algorithm to determine the size distribution in combination with a non-negative least square method and a Phillips-Twomey method to obtain a smooth solution.