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Nishikino, Masaharu; Ishino, Masahiko; Faenov, A.*; Tanaka, Momoko; Hasegawa, Noboru; Pikuz, T.; Inogamov, N. A.*; Kaihori, Takeshi; Kawachi, Tetsuya
no journal, ,
We irradiated the soft X-ray laser pulses at a wavelength of 13.9 nm, the duration time of 7 ps to aluminum (Al), copper (Cu) and gold (Au) surfaces. The modified surfaces were observed with the visible microscope, the scanning electron microscope, and the atomic force microscope. The surface modifications caused by the SXRL irradiations were clearly seen on the surfaces, and it was found that the conical structures having around 100 nm in diameters were formed on the Al surface under a single pulse shot. The conical structures were formed in the features with the average depth of about 40 nm. The modified structure formed on Al surface induced by the SXRL pulse exposure is interesting as the newly structure. Hence, the SXRL beam would be a candidate for a tool of micromachining, which enable to fabricate of three dimensional structures with nano-meter size on Al surface.
Suzuki, Masayuki*; Kiriyama, Hiromitsu; Daito, Izuru; Okada, Hajime; Ochi, Yoshihiro; Sato, Masatoshi*; Yoshii, Takehiro*; Tamaoki, Yoshinori*; Maeda, Junya*; Matsuoka, Shinichi*; et al.
no journal, ,
no abstracts in English
Terada, Takaya; Nishimura, Akihiko; Oka, Kiyoshi
no journal, ,
no abstracts in English
Yamakawa, Koichi
no journal, ,
no abstracts in English
Yogo, Akifumi; Daido, Hiroyuki; Mori, Michiaki; Kiriyama, Hiromitsu; Bulanov, S. V.; Bolton, P.; Sagisaka, Akito; Oishi, Yuji*; Fujii, Takashi*; Nemoto, Koshichi*; et al.
no journal, ,
no abstracts in English
Hasegawa, Noboru; Nishikino, Masaharu; Kaihori, Takeshi; Kawachi, Tetsuya; Yamagiwa, Mitsuru; Yamamoto, Minoru*; Tomita, Takuro*; Minami, Yasuo*; Takei, Ryota*; Suemoto, Toru
no journal, ,
We have developed the femto-second laser pump and soft X-ray laser probe system in order to observe the dynamical processes of the femto-second laser ablation. By using this system, we succeed to obtain the temporal evolution of the soft X-ray reflectivity from the laser induced Pt surface. The results lead that the rate of decrease in the reflectivity of the probe beam has a non-linear relation with the pump laser fluence.
Sakaki, Hironao; Kanasaki, Masato; Fukuda, Yuji; Nishiuchi, Mamiko; Yogo, Akifumi; Jinno, Satoshi; Katagiri, Masaki*; Niita, Koji*
no journal, ,
A single-shot imaging thin scintillator film for online Thomson Parabola spectrometer (TP) has been developed, and the first diagnosis for laser-driven ion by the online TP is demonstrated at J-KAREN laser facility. The energy spectrum of 
4.0 MeV proton is obtained by only this imaging film without using Micro-Channel-Plate that is utilized on online ion diagnosis in general. The general-purpose Monte Carlo particle and heavy ion transport code systems (PHITS) consists various quantum dynamics models is used in the simulation of the scintillator's luminescent diagnostic. The simulation is reasonably predictive not only ion trajectories by the spectrometer but also the luminescence property.
Kanasaki, Masato; Fukuda, Yuji; Sakaki, Hironao; Yogo, Akifumi; Jinno, Satoshi; Nishiuchi, Mamiko; Ogura, Koichi; Kondo, Kiminori; Oda, Keiji*; Yamauchi, Tomoya*
no journal, ,
Recently, solid state nuclear track detectors such as CR-39 detectors have been extensively used in laser-driven ion acceleration experiments, because CR-39 can record the tracks of ion clearly even in the intense fields of photons and high energy electrons. By analyzing the etch pit growth behavior, we can obtain not only the radial intensity distribution of ion beam, but the energy and nuclear species for each ion precisely. This method allows us to measure the maximum energy of proton precisely, which is obtained up to the hundredth place in unit of MeV in the laser-driven particle acceleration experiment.
Fukuda, Yuji
no journal, ,
We present substantial enhancement of the accelerated ion energies up to 10-20 MeV per nucleon by utilizing the unique properties of the cluster-gas target, corresponding to approximately tenfold increase in the ion energies compared to previous experiments using thin foil targets. The demonstrated method can be important in the development of efficient laser ion accelerators for hadron therapy and other applications. We also present the latest experimental results of ion acceleration up to 50 MeV per nucleon using the cluster-gas target with J-KAREN laser system (1 J energy 40 fs laser pulse). By developing integrated ion monitor systems, we try to understand the acceleration mechanism and enhance accelerated ion energies.
Ochi, Yoshihiro; Okada, Hajime; Nagashima, Keisuke; Kosuge, Atsushi; Tanaka, Momoko; Kiriyama, Hiromitsu; Mori, Michiaki; Yoshida, Fumiko; Kong, W.*; Taira, Takunori*
no journal, ,
At Kansai Photon Science Institute, we develop new laser system using Yb:YAG thin-disk as a driver for generating intense THz wave. Specifications of the laser are 1030 nm in wavelength, 1 kHz repetition, 1 ps duration, and 100 mJ in energy, respectively. The laser system consists of two amplifiers; the first is regenerative amplifier and the second is multi-pass amplifier. At the conference, I will present the current status of the regenerative amplifier.