Ikeda, Yujiro; Shimizu, Hirohiko*
Reza Kenkyu, 46(11), p.641 - 646, 2018/11
In viewing significant progresses in technical achievement toward a high-intensity neutron source driven by a high-power laser came up with the high power laser development, we have reviewed the currently most advanced moderator system and neutron optics, which are the key elements for the neutron beam applications. Regarding the moderators, concepts adopted in J-PARC pulsed neutron source, which is one of most advanced system, were described to give a baseline design. Also a new direction of moderator concept is shown, which could be a high brightness candidate for the high-intensity laser driven system. On the neutron optics, the most fundamental consideration is primarily reviewed along with recent progress in new devises for enrichment of neutron-beam characteristics.
Arikawa, Yasunobu*; Ikeda, Yujiro; Shimizu, Hirohiko*; Hanayama, Ryohei*; Kondo, Yasuharu*; Kurosawa, Shunsuke*
Reza Kenkyu, 46(11), p.634 - 640, 2018/11
Compact neutron sources have been used as various diagnostics such as a neutron diffraction, neutron resonant analysis, and neutron radiography. The developments of the neutron detectors are essential for all of these applications, while the techniques are strongly dependent on the neutron energy and the aim of the measurement. This paper reviews neutron detection techniques pertinent to promote compact neutron source uses. Along with general neutron detection systems with conventional counters for slow neutrons, we have highlighted detectors for high energy neutrons with high time resolution and high sensitivity which could be applied in a laser-driven compact neutron source.
Ebisuzaki, Toshikazu*; Wada, Satoshi*; Saito, Norihito*; Fujii, Takashi*; Nishimura, Akihiko
Reza Kenkyu, 45(10), p.664 - 665, 2017/10
no abstracts in English
Reza Kenkyu, 45(7), p.397 - 398, 2017/07
In this special issue, we present laser techniques applied to maintenance and repair of the social infrastructure such as tunnels, electric power generation and transportation, nuclear facilities. Remote sensing, LIBS, LIDAR, remote technologies coupled with lasers and surface cleaning are reviewed in this issue.
Reza Kenkyu, 45(7), p.413 - 417, 2017/07
Inside and surrounding area of reactor buildings of Fukushima Daiichi Nuclear Power Plants became high radiation condition because of radioactive materials release by the accidents caused by earthquake of Pacific coast on eastern and northern Japan. In the stage of emergency response to the accidents, more than 20 robots had been deployed, and some of them had equipped with laser technologies like as laser range finder. In the following decommissioning stage of the plans, operations under higher radiation condition will be required, so that varied laser technologies will be needed to fuse with robot technologies. Laser checker laser analysis would be expected besides laser range finder. However those technologies will be deployed under higher radiation condition, so radiation hardening and control stabilizing should be solved.
Reza Kenkyu, 45(3), p.135 - 136, 2017/03
I describe how important the challenge to Fukushima Daiichi and recovery of this area. From this point of view, scientific and technological trials originated from the disaster and accident should be based on the mission of Fukushima recovery.
Reza Kenkyu, 44(12), p.799 - 803, 2016/12
no abstracts in English
Nishikino, Masaharu; Ishino, Masahiko; Ichimaru, Satoshi*; Hatayama, Masatoshi*; Hasegawa, Noboru; Kawachi, Tetsuya
Reza Gakkai Dai-483-Kai Kenkyukai Hokoku; Tanhacho Ryoshi Bimu Hassei To Sono Oyo, p.25 - 28, 2015/12
X-ray ablation has been recently achieved using plasma soft X-ray lasers (SXRLs), laser plasma soft X-rays, and X-ray free electron lasers. In order to study the interactions between picosecond SXRL beams and material and multi-layered structure surfaces were irradiated with SXRL pulse. Following irradiation, the substrate surface was observed using a scanning electron microscope and an atomic force microscope. The surface modifications caused by the SXRL beam were clearly seen. The multi-layered mirror is the important component for the EUV lithography. Then, we have started the damage test of multi-layered structure, and the surface modifications caused by the SXRL pulse irradiations were confirmed.
Reza Kenkyu, 43(3), p.136 - 137, 2015/03
Recently, technique of pulsed electron beam generation combined with ultrafast laser technology has been developed for realization of time-resolved measurements. A variety of methods such as an electron gun with a photo-cathode and an optical gating of a CW electron beam are proposed and demonstrated. We will compiles topical papers on frontier of pulsed electron beam for research on photoexcited dynamics in one volume of "The Review of Laser Engineering". This paper is a preface for describing the aim and contents of this special volume.
Nishikino, Masaharu; Hasegawa, Noboru; Tomita, Takuro*; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Onishi, Naofumi*; Ito, Atsushi*; Baba, Motoyoshi*; Minami, Yasuo*; Kawachi, Tetsuya; et al.
Reza Gakkai Dai-471-Kai Kenkyukai Hokoku; Tanhacho Ryoshi Bimu Hassei To Sono Oyo, p.9 - 12, 2014/12
no abstracts in English
Akaoka, Katsuaki; Miyabe, Masabumi; Otobe, Haruyoshi; Wakaida, Ikuo
Reza Kenkyu, 42(12), p.918 - 922, 2014/12
For the remote analysis of the next generation nuclear fuel material containing minor actinide (MA), Laser Induced Breakdown Spectroscopy (LIBS) was applied to uranium oxide (UO) including a small amount of neodymium oxide (NdO) as a simulated sample of MA. By using deconvolution technique for the spectra of Nd in U, the complex, overlapped and confused spectra were separated and their actual intensities were determined. As a result, the calibration curve with good linearity and the detection limit of less than 700 ppm were demonstrated.
Ozu, Akira; Tachi, Yoshiaki; Arita, Yuji*
Reza Kenkyu, 42(12), p.913 - 917, 2014/12
Laser-induced breakdown spectroscopy (LIBS) analysis has been applied to the molten alloy production process, in which simulated metals (Zr, Cu, Sm, Ce) are used instead of nuclear metallic fuels contained minor actinide (MA), with the aim of in-situ monitoring the elementary composition of the surface of the molten alloy in a chamber and vapor particles generated from the surface of the molten alloy. The variation in the ratio of elementary composition of the surface of the molten alloy in the crucible was successfully observed depending on temperature of the crucible. The elementary composition of the vapor particles appeared in the molten alloy chamber was also measured. The practical experimental results show that LIBS technique is very useful for investigating the elementary composition in the process and understanding the behavior of molten alloy in the crucible.
Oba, Hironori; Saeki, Morihisa; Wakaida, Ikuo
Reza Kenkyu, 42(12), p.892 - 896, 2014/12
Laser-induced breakdown spectroscopy (LIBS) is an attractive technique for determining elemental composition in real time, in-situ and remotely without any sample preparation. The LIBS analysis of metal ions in an aqueous solution is available in process control and environmental monitoring. In the present paper, we have reviewed the LIBS methods for a liquid phase that tried to improve the detection sensitivity. We have performed the LIBS measurement with the sheet flow for the simultaneous determination of elements in the simulated high-level radioactive waste liquid and have discussed on the application possibility as a tool for online process monitoring.
Nishikino, Masaharu; Kawachi, Tetsuya; Daido, Hiroyuki
Reza Kenkyu, 42(8), p.678 - 679, 2014/08
no abstracts in English
Kiriyama, Hiromitsu; Mori, Michiaki; Suzuki, Masayuki*; Daito, Izuru*; Okada, Hajime; Ochi, Yoshihiro; Tanaka, Momoko; Sato, Masatoshi*; Tamaoki, Yoshinori*; Yoshii, Takehiro*; et al.
Reza Kenkyu, 42(6), p.441 - 447, 2014/06
We describe three specific high power laser systems that are being developed in our laboratory for many applications in high field science, nonlinear optics and material processing. We report on a femtosecond petawatt-class Ti:sapphire chirped-pulse amplification laser system that can produce a pulse energy of 20 J of 40 fs pulse duration, a picosecond high intensity Yb:YAG chirped-pulse amplification laser system that can generate a pulse energy of 100 mJ of 0.5 ps pulse duration, and a nanosecond high repetition rate Nd:YAG laser system that can provide an average power of 360 W with a pulse duration of 30 ns delivered at a 1 kHz repetition rate. We discuss the basic design aspects and present the results from our experimental investigations of these laser systems.
Seto, Keita*; Koga, J. K.; Zhang, S.*
Reza Kenkyu, 42(2), p.174 - 178, 2014/02
Sagisaka, Akito; Pirozhkov, A. S.; Nishiuchi, Mamiko; Ogura, Koichi; Sakaki, Hironao; Yogo, Akifumi; Mori, Michiaki; Kiriyama, Hiromitsu; Okada, Hajime; Kanazawa, Shuhei; et al.
Reza Kenkyu, 42(2), p.160 - 162, 2014/02
High-intensity laser and thin-foil interactions produce high-energy particles, hard X-ray, high-order harmonics, and terahertz radiation. A proton beam driven by a high-intensity laser has received attention as a compact ion source for medical and other applications. We have measured the proton yield from thin-foil targets irradiated with a high-intensity Ti:sapphire laser (J-KAREN) at JAEA. The longitudinal extent of the preformed plasma protruding from the front surface of the target is reduced by decreasing the duration of the amplified spontaneous emission (ASE) before the main pulse. The maximum proton energy in the target normal direction increases when the size of the preformed plasma is controlled.
Sakaki, Hironao; Sato, Tatsuhiko; Kai, Tetsuya
Reza Kenkyu, 42(2), p.163 - 167, 2014/02
A general-purpose Monte Carlo particle and heavy ion transport code system (PHITS), which consists of various quantum dynamics models, was used to study laser-driven ion acceleration. Our simulation reasonably predicted not only the laser-driven ion's trajectories detected by the monitors but also the radiation shielding of these particles.
Kanasaki, Masato; Fukuda, Yuji; Kondo, Kiminori; Oda, Keiji*; Yamauchi, Tomoya*
Reza Kenkyu, 42(2), p.168 - 173, 2014/02
In laser-driven ion acceleration experiments using the cluster-gas targets, a significant amount of fast electrons, which drives the ion acceleration, are produced along with high energy ions with several-tens of MeV. In our recent experiment using CO clusters embedded in H gas conducted with the J-KAREN laser facility (1 J, 40 fs) at JAEA-KPSI, the maximum energy of electrons reaches up to 200 MeV. Such fast electrons can produce photo-neutrons via bremsstrahlung processes followed by photo-nuclear reactions. When the CR-39 is exposed to photo-neutrons, it records etchable tracks of generated ions depending on their species and energy as background noises. In order to diagnose the laser-accelerated protons precisely using CR-39, we have developed the discrimination method for laser-accelerated protons and photo-neutrons on CR-39 based on the incident angle and incident energy.
Reza Kenkyu, 42(2), p.106 - 110, 2014/02
An instantaneous peak power generated with the advanced laser technology reached over peta-watt now. The focused intensity is possibly in the ultra-relativistic region, which opens a new experimental research. Some attractive themes are introduced.