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Journal Articles

Design of accelerator-driven system consistent to partitioning technology

Sugawara, Takanori; Ban, Yasutoshi; Katano, Ryota; Tateno, Haruka; Nishihara, Kenji

Proceedings of International Conference on the Management of Spent Fuel from Nuclear Power Reactors 2019 (Internet), 9 Pages, 2019/06

The JAEA has proposed the double-strata strategy which will introduce a dedicated minor actinide (MA) transmutation cycle using an accelerator-driven system (ADS). In the previous study, the ideal fuel condition was supposed in the neutronics design of the ADS. For example, impurities such as rare earth (RE) nuclides which would accompany with MA, were not assumed. However, these nuclides would accompany with the ADS fuel and the capture reaction of these nuclides deteriorates the neutron economy of the ADS core. This study investigates a new fuel composition based on the SELECT (Solvent Extraction from Liquid-waste using Extractants of CHON-type for Transmutation) process proposed by JAEA. By performing the neutronics calculation of the ADS with the new fuel composition, a feasibility of the new fuel composition will be investigated.

Journal Articles

Development of high resistant anti-reflection coating by using Al$$_{2}$$O$$_{3}$$/SiO$$_{2}$$ multilayer

Ochi, Yoshihiro; Nagashima, Keisuke; Okada, Hajime; Tanaka, Momoko; Tateno, Ryo*; Furukawa, Yasuyuki*; Sugiyama, Akira

Proceedings of SPIE, Vol.8885, p.88851Z_1 - 88851Z_6, 2013/11

 Times Cited Count:4 Percentile:89.54

We designed and fabricated high damage-resistant AR coating using Al$$_{2}$$O$$_{3}$$/SiO$$_{2}$$ layers. As a result of irradiation test using 500 ps pulses at 1 kHz, the damage threshold of the AR coating was estimated to be over 36 J/cm$$^{2}$$ (average value). We also fabricated high reflection (HR) mirrors using Al$$_{2}$$O$$_{3}$$/SiO$$_{2}$$ layers added on Ta$$_{2}$$O$$_{5}$$/SiO$$_{2}$$ layers and measured damage threshold of them for 7 ns, 500 ps, and 1 ps pulses.

Journal Articles

Negative effect of crystallization on the mechanism of laser damage in a HfO$$_{2}$$/SiO$$_{2}$$ multilayer

Tateno, Ryo*; Okada, Hajime; Otobe, Tomohito; Kawase, Keigo*; Koga, J. K.; Kosuge, Atsushi; Nagashima, Keisuke; Sugiyama, Akira; Kashiwagi, Kunihiro*

Journal of Applied Physics, 112(12), p.123103_1 - 123103_3, 2012/12

 Times Cited Count:3 Percentile:15.25(Physics, Applied)

Elucidation of the mechanisms of laser damage is indispensable in realizing high resistance mirrors for the next generation of ultra-short pulse high intensity lasers. In this study, the surface and a section of the laser-damaged area of a laser mirror were observed with a laser microscope and a transmission electron microscope (cross-sectional TEM), respectively. A grain boundary of HfO$$_{2}$$ microcrystal was observed in the damaged area. This observation, and an evaluation of the mirror's damage resistance showed that the formation of crystals in the multilayer mirror is one of the major determinants of damage resistance.

Journal Articles

"J-KAREN"; High intensity, high contrast laser

Kiriyama, Hiromitsu; Mori, Michiaki; Nakai, Yoshiki; Shimomura, Takuya*; Tanoue, Manabu*; Okada, Hajime; Sasao, Hajime; Wakai, Daisuke*; Kondo, Shuji; Kanazawa, Shuhei; et al.

JAEA-Conf 2009-007, p.97 - 100, 2010/03

no abstracts in English

Oral presentation

Research activities in our laser R&D group; Present & future

Sugiyama, Akira; Kondo, Kiminori; Kiriyama, Hiromitsu; Ochi, Yoshihiro; Tanaka, Momoko; Nakai, Yoshiki; Sasao, Hajime; Tateno, Ryo; Okada, Hajime; Koike, Masato

no journal, , 

Our laser research and development group was newly founded in this April. The aim of our group is to build up powerful light sources promoting the high-peak optical field science such as laser particle acceleration and quantum beam generation, etc. To realize our mission, we will intend to develop the essential technology for the upgrade of J-KAREN and TOPAZ systems. These essential technologies that will be developed in two laser systems can be absolutely used for the advanced laser light source in near future.

Oral presentation

Optical thin film with high damage resistance for laser device

Tateno, Ryo; Sugiyama, Akira; Harada, Yoshihisa*; Ihara, Masahiro*; Kashiwagi, Kunihiro*

no journal, , 

no abstracts in English

Oral presentation

Annual progress and future plans of Laser R&D Group

Sugiyama, Akira; Kiriyama, Hiromitsu; Ochi, Yoshihiro; Tanaka, Momoko; Nakai, Yoshiki; Sasao, Hajime; Tateno, Ryo; Okada, Hajime; Kosuge, Atsushi; Tsubouchi, Masaaki

no journal, , 

The main subject of our group is upgrade of J-KAREN and TOPAZ laser systems. The J-KAREN achieves the potential for generating a peak power of 500 TW, and exceeds a contrast ratio of 10E10. The TOPAZ achieves pulse power of 15 J at a repetition rate of 0.1 Hz. We also started a development of another laser system named QUADRA (Quality Ultra ADvanced RAdiation Source) in C-Phost. The QUADRA system is a high averaged short pulse laser pumped by high power LD at kHz repetition rate. This development is essential for the developments of other new laser systems in the next 5-year program of JAEA.

Oral presentation

Nondestructive assay of Pu, U and MA's in spent fuel by usinga mono-energetic $$gamma$$-ray beam, 1; Facility design and R&D status

Hajima, Ryoichi; Hayakawa, Takehito; Kikuzawa, Nobuhiro; Shizuma, Toshiyuki; Nishimori, Nobuyuki; Nagai, Ryoji; Sawamura, Masaru; Kawase, Keigo; Kosuge, Atsushi; Tateno, Ryo; et al.

no journal, , 

no abstracts in English

Oral presentation

Negative effect of crystallization on the mechanism of laser damage in HfO$$_{2}$$/SiO$$_{2}$$ multilayer

Tateno, Ryo*; Okada, Hajime; Kosuge, Atsushi; Nagashima, Keisuke; Sugiyama, Akira; Kashiwagi, Kunihiro*

no journal, , 

Elucidation for the mechanism of laser damage is indispensable to realize a high resistance mirror for the ultra-short pulse high intense lasers of the next generation. In this study, the surface and a section of a laser-damaged area of a laser mirror were observed with a laser microscope and a transmission electron microscope (cross-sectional TEM), respectively. A grain boundary of HfO$$_{2}$$ microcrystal was observed in the damaged area. This observation, and an evaluation of the mirror's damage resistance showed that the formation of crystals in the multilayer mirror is one of the major determinants of damage resistance.

Oral presentation

High resistant multilayer coatings for thin-disk laser amplifier

Ochi, Yoshihiro; Nagashima, Keisuke; Maruyama, Momoko; Okada, Hajime; Sugiyama, Akira; Tateno, Ryo*; Furukawa, Yasuyuki*

no journal, , 

We designed and fabricated high resistant AR and HR coatings using Al$$_{2}$$O$$_{3}$$ layer for Yb:YAG tin-disk amplifier. The damage threshold fluences for 520 ps pulse (AR, HR) and 1.2 ps pulse (HR only) were measured by uncompressed and compressed pulses, respectively, from the regenerative amplifier in QUADRA-T. As results, the damage threshold fluence of the AR coating of Al$$_{2}$$O$$_{3}$$/SiO$$_{2}$$ multilayer was 75 J/cm$$^{2}$$ for 520 ps pulse. This is satisfied out target value 40 J/cm$$^{2}$$ to use in the amplifiers. For the HR coating, the highest damage threshold fluences, 2.4 J/cm$$^{2}$$ for 1.2 ps pulse and 123.6 J/cm$$^{2}$$ for 520 ps pulse, respectively, were obtained by manipulating Al$$_{2}$$O$$_{3}$$/SiO$$_{2}$$ layer thickness to set a point of the maximum electric field in the SiO$$_{2}$$ layer.

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