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Strasser, P.*; Abe, Mitsushi*; Aoki, Masaharu*; Choi, S.*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; et al.
EPJ Web of Conferences, 198, p.00003_1 - 00003_8, 2019/01
Times Cited Count：13 Percentile：99.06(Quantum Science & Technology)Strasser, P.*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; Ito, Takashi; Iwasaki, Masahiko*; et al.
Hyperfine Interactions, 237(1), p.124_1 - 124_9, 2016/12
Times Cited Count：7 Percentile：90.97(Physics, Atomic, Molecular & Chemical)Abe, Hiroshi; Shimomura, Takuya; Tokuhira, Shinnosuke*; Shimada, Yukihiro*; Takenaka, Yusuke*; Furuyama, Yuta*; Nishimura, Akihiko; Uchida, Hirohisa*; Daido, Hiroyuki; Oshima, Takeshi
Proceedings of 7th International Congress on Laser Advanced Materials Processing (LAMP 2015) (Internet), 4 Pages, 2015/08
A short pulse laser (the nanosecond and femtosecond) was applied to hydrogen absorbing alloys surface layer, and a surface modification experiment was put into effective to aim at improvement of hydrogen adsorption functionally. It was investigated about correlation between an initial hydrogen absorption reaction rate of hydrogen alloys and a laser irradiation in this research. The laser irradiation condition was done with pulse width 100 fsec and energy 0.2 - 3.4 mJ/pulse. It blazed down on hydrogen absorbing alloys (LaNi
Al
) and changed local order in the surface. As a result, the initial hydrogen absorption reaction rate was 1.5 - 3.0 times as fast as a irradiated sample, and the result and laser irradiated sample found out that a hydrogen absorption function improves. A laser irradiation can conclude to be effective in surface modification of the hydrogen storage materials.
Nishimura, Akihiko; Takenaka, Yusuke*; Furuyama, Takehiro*; Shimomura, Takuya; Terada, Takaya; Daido, Hiroyuki
Journal of Laser Micro/Nanoengineering, 9(3), p.221 - 224, 2014/11
Times Cited Count：0 Percentile：0(Nanoscience & Nanotechnology)Heat resistant FBG sensors were developed by femtosecond laser processing to apply them to high temperature operated piping system of nuclear power plants. The FBG sensor was installed on the surface of a steel blade and a vibration test was conducted to detect the resonant vibration frequency of the vibrating blade. The FBG sensor had the heatproof performance at 600
C. A frequency stabilized sensing system using a tunable laser was tested for structural health monitoring in daily operation of nuclear power plants. The FBG sensor was installed on the surface of a steel blade for vibration induced strain measurements. Welding, brazing, soldering and noble metal powder adhesive were discussed for molding the FBG sensors.
Nishimura, Akihiko; Terada, Takaya; Takenaka, Yusuke*; Furuyama, Takehiro*; Shimomura, Takuya
Proceedings of 22nd International Conference on Nuclear Engineering (ICONE-22) (DVD-ROM), 6 Pages, 2014/07
Since 2007, JAEA has been developing laser based technologies of structural health monitoring. The FBG sensor made by femtosecond laser processing will be the best candidate. To make the best use of the heat resistant characteristic, the FBG sensor was embedded in metal mold by laser cladding. A groove was processed to the surface of a SUS metal plate. We used a QCW laser to weld a filler wire on the plate. A series of weld beads perfectly formed a sealing clad on the groove. Though the FBG sensor was buried tightly, no degradation on the reflection spectrum was detected after the processing. The FBG sensor could detect the vibration of the plate caused by impact shocks and audio vibration. The reflection peak of the FBG sensor under laser cladding condition was shifted to be 6 nm. We demonstrated that the corresponded temperature derive from the reflection peak shift reached 600 degrees in heat shock experiments. The installation procedure of a FBG sensor using a portable laser cladding machine was described.
Nishimura, Akihiko; Takenaka, Yusuke*; Furuyama, Takehiro*; Shimomura, Takuya; Terada, Takaya; Daido, Hiroyuki
Proceedings of 1st Smart Laser Processing Conference 2014 (SLPC 2014), 4 Pages, 2014/04
Heat resistant FBG sensors were developed by femtosecond laser processing. In order to apply them to piping system of nuclear power plants, vibration test under high temperature was demonstrated. The FBG sensor had the heatproof performance at 600C. A frequency stabilized sensing system using a tunable laser was tested for structural health monitoring in daily operation of nuclear power plants. The FBG sensor was installed on the surface of a steel blade for vibration induced strain measurements. Welding, brazing, soldering and noble metal powder adhesive were discussed for molding the FBG sensors.
Yogo, Akifumi; Sato, Katsutoshi; Nishikino, Masaharu; Maeda, Takuya*; Sakaki, Hironao; Hori, Toshihiko*; Ogura, Koichi; Nishiuchi, Mamiko; Teshima, Teruki*; Nishimura, Hiroaki*; et al.
Japanese Journal of Applied Physics, 50(10), p.106401_1 - 106401_7, 2011/10
Times Cited Count：8 Percentile：34.67(Physics, Applied)Zhang, Z.*; Nishikino, Masaharu; Nishimura, Hiroaki*; Kawachi, Tetsuya; Pirozhkov, A. S.; Sagisaka, Akito; Orimo, Satoshi; Ogura, Koichi; Yogo, Akifumi; Okano, Yasuaki*; et al.
Optics Express (Internet), 19(5), p.4560 - 4565, 2011/02
Times Cited Count：19 Percentile：66.78(Optics)
line emission from Mo and Ag plate were experimentally studied by using ultra-high intensity, clean femtosecond laser pulses. Absolutely yield of X-rays at 17 keV from Mo and 22 keV from Ag were measured as a function of the laser pulse contrast ratio and irradiation intensity. Significant enhancement of yields were obtained for both Mo and Ag with higher contrast ratios and high irradiance. The conversion efficiencies of 4.28 
10
/sr for Mo and 4.84 10/sr for Ag, the highest values ever obtained, have been demonstarted with the contrast ratio of 10
to 10
.
Nishimura, Akihiko; Shobu, Takahisa; Oka, Kiyoshi; Yamaguchi, Toshihiko; Shimada, Yukihiro; Mihalache, O.; Tagawa, Akihiro; Yamashita, Takuya
Reza Kako Gakkai-Shi, 17(4), p.207 - 212, 2010/10
A prototype probe system with a hybrid optical fiber scope was designed for inspecting and re-pairing the micro cracks on heat exchanger tubes in fast breeder reactors (FBRs). It comprised a laser processing head combined with an eddy current testing unit. Ultrashort laser pulse ablation was used to remove work-hardened layers. And spot laser welding was used to repair the micro cracks. This system has both safe and economical options for the maintenance of FBRs because it extends the lifetime of the heat exchangers.
Oka, Kiyoshi; Nishimura, Akihiko; Seki, Takeshi*; Akatsu, Tomohiro*; Yamashita, Takuya
Hozengaku, 8(4), p.37 - 42, 2010/01
A composite-type optical fiberscope was combined with a laser processing head to repair heat exchange pipes of Fast Breeder Reactor (FBR). The head can rotate axially and move back and forth longitudinally in the 1-inch pipes. The property of fiberscope and the motion of the head can successfully observe the pipe's inner surface to find the cracks which should be repaired by laser welding. The project, which aims for developing the integrated system of inspection and repair, proposes an effective cost reduction for maintenance of FBRs by extension of the heat exchanger's lifetime. This report describes the outline of the laser processing head and the basic performance.
Nishimura, Akihiko; Oka, Kiyoshi; Yamaguchi, Toshihiko; Akatsu, Tomohiro*; Seki, Takeshi*; Mihalache, O.; Shimada, Yukihiro; Tagawa, Akihiro; Yamashita, Takuya
Nihon Hozen Gakkai Dai-6-Kai Gakujutsu Koenkai Yoshishu, p.250 - 253, 2009/08
In order to maintain FBR heat exchanger tubes, a new probe system was designed. A coupling unit and operational software are key components in the second year. The coupling unit to combine a high energy laser beam and optical fiberscope images was developed. The operational software successfully controlled an eddy current testing device and a laser processing head.
Yamashita, Takuya; Nishimura, Akihiko; Tsuchida, Noboru; Yamaguchi, Toshihiko; Oka, Kiyoshi; Fujiki, Kazunari*; Shimada, Yukihiro
no journal, ,
The preservation techniques of safety research on "Monju" and the next generation Fast Breeder Reactors have been exhibited. The exhibition consists of (1) EMAT, (2) ECT, (3) Laser Processing Head. Both (1) and (2) are the checking techniques for the cracks on nuclear power plants, while (3) is the repairing technique for the heat exchanger. In 2009, these three techniques will have been integrated to be a new probing system. The hybrid optical fiber has been involved in (3), which the project "photo-Medical Valley in JAEA-KANSAI are now developing as a fiber surgery device.
Murakami, Makoto*; Kawamura, Makoto; Oi, Takao; Makino, Hitoshi; Nishimura, Takuya*; Umeda, Koji; Seo, Toshihiro
no journal, ,
no abstracts in English
Yamaguchi, Toshihiko; Mihalache, O.; Oka, Kiyoshi; Yamashita, Takuya; Tagawa, Akihiro; Nishimura, Akihiko
no journal, ,
no abstracts in English
Oka, Kiyoshi; Nishimura, Akihiko; Yamashita, Takuya
no journal, ,
no abstracts in English
Nishimura, Akihiko; Oka, Kiyoshi; Yamaguchi, Toshihiko; Mihalache, O.; Tagawa, Akihiro; Yamashita, Takuya
no journal, ,
The inspection and repairing probe system for SG tubes of FBR was specially designed. A hybrid optical fiber scope was fabricated. A laser processing head and the hybrid optical fiber scope were combined to repair cracks inside wall of the SG tubes. An eddy current testing unit successfully detected the cracks. All these units will be assembled to be a new probing system by the end of next year. This project was financially supported by MEXT through JST.
Murakami, Makoto*; Kawamura, Makoto; Sasaki, Hisashi*; Makino, Hitoshi; Seo, Toshihiro; Nishimura, Takuya*; Umeda, Koji; Oi, Takao; Geshi, Nobuo*; Oikawa, Teruki*
no journal, ,
The volcanic scenario has mainly been conventionally examined from a viewpoint of empiricism based on the understanding of physics and/or scientific mechanism of volcanic activity. However, when a volcanic scenario is examined only based on the empiricism of a volcano, there is a possibility that the phenomena which the volcano had not experienced in the past may fall out from the scenario. Therefore, it is necessary to follow up omission by collecting information from various volcanoes. The purpose of this research is to develop the scenario analysis technique which can perform prediction of progress of volcanic activity by applying the FEP analysis technique examined by High level radioactive waste geological disposal. As a result, a volcanic scenario can be built by applying the FEP analysis technique. It was understood that the FEP analysis technique developed by geological isolation can apply also to the field of other technology. We will collect information further and apply this technique to other volcanoes. We consider improvement of the FEP analysis technique based on the result of this study.
Nishimura, Akihiko; Oka, Kiyoshi; Yamaguchi, Toshihiko; Mihalache, O.; Tagawa, Akihiro; Yamashita, Takuya
no journal, ,
no abstracts in English
Mori, Michiaki; Ogura, Koichi; Yogo, Akifumi; Nishiuchi, Mamiko; Kiriyama, Hiromitsu; Pirozhkov, A. S.; Sagisaka, Akito; Orimo, Satoshi; Tampo, Motonobu; Daito, Izuru; et al.
no journal, ,
Experimental studies of laser-driven ion acceleration aimed at ion therapy for cancer treatment are being conducted at the PMRC of JAEA using the J-KAREN Ti:Sapphire laser system at JAEA's APRC. In recent experiments thin foil targets have been irradiated with focused 38 fs laser pulses at the 1.8J laser energy. The energy spectrum of the proton beam is observed to extend to a cut-off value in excess of 7-MeV. Our results expose the prospects and challenges associated with developing a laser-driven ion therapy facility.
Nishiuchi, Mamiko; Ogura, Koichi; Sagisaka, Akito; Yogo, Akifumi; Pirozhkov, A. S.; Mori, Michiaki; Kiriyama, Hiromitsu; Orimo, Satoshi; Tampo, Motonobu; Daito, Izuru; et al.
no journal, ,
no abstracts in English
