Design and actual performance of J-PARC 3 GeV rapid cycling synchrotron for high-intensity operation

Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.

Journal of Nuclear Science and Technology, 59(9), p.1174 - 1205, 2022/09

https://doi.org/10.1080/00223131.2022.2038301

In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.

Visualizing cation vacancies in Ce:GdAlGaO scintillators by gamma-ray-induced positron annihilation lifetime spectroscopy

Fujimori, Kosuke*; Kitaura, Mamoru*; Taira, Yoshitaka*; Fujimoto, Masaki*; Zen, H.*; Watanabe, Shinta*; Kamada, Kei*; Okano, Yasuaki*; Kato, Masahiro*; Hosaka, Masahito*; et al.

Applied Physics Express, 13(8), p.085505_1 - 085505_4, 2020/08

https://doi.org/10.35848/1882-0786/aba0dd

To clarify the existence of cation vacancies in Ce-doped GdAlGaO (Ce:GAGG) scintillators, we performed gamma-ray-induced positron annihilation lifetime spectroscopy (GiPALS). GiPAL spectra of GAGG and Ce:GAGG comprised two exponential decay components, which were assigned to positron annihilation at bulk and defect states. By an analogy with Ce:YAlO, the defect-related component was attributed to Al/Ga-O divacancy complexes. This component was weaker for Ce, Mg:GAGG, which correlated with the suppression of shallow electron traps responsible for phosphorescence. Oxygen vacancies were charge compensators for Al/Ga vacancies. The lifetime of the defect-related component was significantly changed by Mg co-doping. This was understood by considering aggregates of Mg ions at Al/Ga sites with oxygen vacancies, which resulted in the formation of vacancy clusters.

The Effects of plutonium content and self-irradiation on thermal conductivity of mixed oxide fuel

Ikusawa, Yoshihisa; Morimoto, Kyoichi; Kato, Masato; Saito, Kosuke; Uno, Masayoshi*

Nuclear Technology, 205(3), p.474 - 485, 2019/03

https://doi.org/10.1080/00295450.2018.1494999

This study evaluated the effects of plutonium content and self-irradiation on the thermal conductivity of mixed-oxide (MOX) fuel. Samples of UO fuel and various MOX fuels were tested. The MOX fuels had a range of plutonium contents, and some samples were stored for 20 years. The thermal conductivity of these samples was determined from thermal diffusivity measurements taken via laser flash analysis. Although the thermal conductivity decreased with increasing plutonium content, this effect was slight. The effect of self-irradiation was investigated using the stored samples. The reduction in thermal conductivity caused by self-irradiation depended on the plutonium content, its isotopic composition, and storage time. The reduction in thermal conductivity over 20 years' storage can be predicted from the change of lattice parameter. In addition, the decrease in thermal conductivity caused by self-irradiation was recovered with heat treatment, and recovered almost completely at temperatures over 1200 K. From these evaluation results, we formulated an equation for thermal conductivity that is based on the classical phonon-transport model. This equation can predict the thermal conductivity of MOX fuel thermal conductivity by accounting for the influences of plutonium content and self-irradiation.

Development of multi-colored neutron talbot-lau interferometer with absorption grating fabricated by imprinting method of metallic glass

Seki, Yoshichika; Shinohara, Takenao; Parker, J. D.*; Yashiro, Wataru*; Momose, Atsushi*; Kato, Kosuke*; Kato, Hidemi*; Sadeghilaridjani, M.*; Otake, Yoshie*; Kiyanagi, Yoshiaki*

Journal of the Physical Society of Japan, 86(4), p.044001_1 - 044001_5, 2017/03

https://doi.org/10.7566/JPSJ.86.044001

For the effective phase imaging at pulsed neutron sources, we have designed and developed the multi-colored Talbot-Lau interferometer which works at several wavelengths. At the Energy Resolved Neutron Imaging System RADEN in J-PARC, we demonstrated its operation by observing the visibilities of moire fringes derived from different wavelengths (0.25, 0.50, and 0.75 nm). We also investigated the variation of moire fringes dependent on the wavelength resolution from 18% to 50% and showed the advantage of pulsed beams. At the central wavelength of 0.5 nm, we have succeeded in interferometric imaging for the samples of metal rods made of aluminum, lead, and copper. An absorption grating as an analyzer was fabricated by imprinting of metallic glass for the first time, and showed a clear moire fringe with the high visibility of 68% and a well-controlled shape in comparison with previous ones fabricated by oblique evaporation of gadolinium.

The Study of the magnetization process of Fe film by magnetic Compton scattering and Mssbauer spectroscopy

Agui, Akane; Masuda, Ryo*; Kobayashi, Yasuhiro*; Kato, Tadashi*; Emoto, Shun*; Suzuki, Kosuke*; Sakurai, Hiroshi*

Journal of Magnetism and Magnetic Materials, 408, p.41 - 45, 2016/06

AA2015-0849.pdf:1.54MB

https://doi.org/10.1016/j.jmmm.2016.02.016

We investigated the magnetization process of Fe (110) film using the field dependence of magnetic Compton scattering and Mssbauer spectroscopy. From the magnetic Compton profiles, the spin and orbital magnetic moment specific magnetization versus magnetizing field curves were obtained. From the Mssbauer spectra, the angles between the magnetizing field and the magnetic moment were obtained. It was found that the magnetizing field dependence of the ratio between orbital moment and spin moment was related to the angles between the magnetizing field and the magnetic moment. We indicate that the magnetic field dependence of the orbital magnetic moment plays a role in the magnetization process.

Benchmark test of JENDL-4.0 with TOF experiments at Osaka Univ./OKTAVIAN

Kato, Yoshinari*; Takakura, Kosuke; Ota, Masayuki; Ochiai, Kentaro; Sato, Satoshi; Konno, Chikara

Progress in Nuclear Science and Technology (Internet), 4, p.596 - 600, 2014/04

http://www.aesj.or.jp/publication/pnst004/data/596_600.pdf

We have performed benchmark tests for JENDL-4.0 released last year in shielding and fusion neutronics fields. Now we analyze OKTAVIAN TOF experiments (CF, Si, Ti, Cr, Mn, Co, Cu, As, Se, Zr, Nb, Mo, W) with JENDL-4.0 in order to validate JENDL-4.0. For comparison we also do with the older version JENDL-3.3 and other recent nuclear data libraries (ENDF/B-VII.0, JEFF-3.11). The Monte Carlo code MCNP-4C was used for these analyses. We adopted the official ACE files for JENDL-4.0, JENDL-3.3, JEFF-3.1 and ENDF/B-VII.0. As a result, the following results are obtained through comparison between calculation and measured results. (1) Si, As, Se, Mo, W : Calculation results with JENDL-4.0 agree with the measured ones better than those with JENDL-3.3. (2) CF, Co, Cu, Ti, Zr : Calculation results with JENDL-4.0 are almost the same as those with JENDL-3.3. (3) Cr, Mn, Nb : Calculation results with JENDL-4.0 are partially better and partially worse than those with JENDL-3.3.

Electrical characterization of GaN containing nitrogen vacancies introduced by electron irradiation

Kato, Masashi*; Fukushima, Keisuke*; Kasuga, Masanobu*; Kito, Kosuke*; Ichimura, Masaya*; Kanechika, Masakazu*; Ishiguro, Osamu*; Kachi, Tetsu*; Oshima, Takeshi

no journal, , 

no abstracts in English

Benchmark test of MATXSLIB-J40 produced from JENDL-4.0

Konno, Chikara; Kato, Yoshinari; Takakura, Kosuke; Ochiai, Kentaro; Sato, Satoshi

no journal, , 

JENDL-4, the major revised version of Japanese Evaluated Nuclear Data Library (JENDL), was released in May, 2010. Its official multigroup library MATXSLIB-4.0 of 199 neutron groups and 42 groups with up-scattering data and thermal scattering law data was also released in September, 2010. In this study we examined a validation of MATXSLIB-J40 through analyses of benchmark experiments at JAEA/FNS with Sn codes and the Monte Carlo code MCNP. As a result, the following results are obtained. (1) The calculated results with Sn codes and MATXSLIB-J40 agree well with the measured data and the calculated ones with MCNP. The self-shielding correction in MATXSLIB-J40 has no problem. (2) It is notable that thermal neutron peaks, which were hard to represent, are adequately calculated. It is strongly recommended that a multigroup library of the next Fusion Evaluated Nuclear Data Library (FENDL), FENDL-3, should also have 199 neutron groups, up-scattering data and thermal scattering law data.

Benchmark test of JENDL-4.0 with TOF experiments at Osaka Univ./OKTAVIAN, 2

Kato, Yoshinari; Ochiai, Kentaro; Takakura, Kosuke; Sato, Satoshi; Konno, Chikara

no journal, , 

no abstracts in English

Study on the physical properties of non-stoichiometric oxide fuels with high minor actinide contents, 6; Evaluation of fuel properties for simulated MA containing oxide fuel

Muta, Hiroaki*; Kato, Naoki*; Tanaka, Kosuke; Matsuda, Tetsushi*; Oishi, Yuji*; Kurosaki, Ken*; Yamanaka, Shinsuke*

no journal, , 

Effect of MA and FP addition on thermo-mechanical properties of UO were investigated.