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Al
GaO
scintillators by gamma-ray-induced positron annihilation lifetime spectroscopyFujimori, 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
Times Cited Count：1 Percentile：24.67(Physics, Applied)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:YAl
O, 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.
Cappia, F.*; Tanaka, Kosuke; Kato, Masato; McClellan, K.*; Harp, J.*
Journal of Nuclear Materials, 533, p.152076_1 - 152076_14, 2020/05
Times Cited Count：1 Percentile：39.17(Materials Science, Multidisciplinary)Ikusawa, Yoshihisa; Morimoto, Kyoichi; Kato, Masato; Saito, Kosuke; Uno, Masayoshi*
Nuclear Technology, 205(3), p.474 - 485, 2019/03
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)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.
Sakamoto, Tetsuo*; Morita, Masato*; Kanenari, Keita*; Tomita, Hideki*; Sonnenschein, V.*; Saito, Kosuke*; Ohashi, Masaya*; Kato, Kotaro*; Iguchi, Tetsuo*; Kawai, Toshihide*; et al.
Analytical Sciences, 34(11), p.1265 - 1270, 2018/11
Times Cited Count：7 Percentile：39.71(Chemistry, Analytical)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
Times Cited Count：13 Percentile：75.09(Physics, Multidisciplinary)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.
(Al,Ga)O scintillator Compton camera mounted on an unmanned helicopterShikaze, Yoshiaki; Nishizawa, Yukiyasu; Sanada, Yukihisa; Torii, Tatsuo; Jiang, J.*; Shimazoe, Kenji*; Takahashi, Hiroyuki*; Yoshino, Masao*; Ito, Shigeki*; Endo, Takanori*; et al.
Journal of Nuclear Science and Technology, 53(12), p.1907 - 1918, 2016/12
Times Cited Count：24 Percentile：96.18(Nuclear Science & Technology)The Compton camera was improved for use with the unmanned helicopter. Increase of the scintillator array from 4
4 to 88 and expanse of the distance between the two layers contributed to the improvements of detection efficiency and angular resolution, respectively. Measurements were performed over the riverbed of the Ukedo river of Namie town in Fukushima Prefecture. By programming of flight path and speed, the areas of 65 m 60 m and 65 m 180 m were measured during about 20 and 30 minutes, respectively. By the analysis the air dose rate maps at 1 m height were obtained precisely with the angular resolution corresponding to the position resolution of about 10 m from 10 m height. Hovering flights were executed over the hot spot areas for 10-20 minutes at 5-20 m height. By using the reconstruction software the 
-ray images including the hot spots were obtained with the angular resolution same as that evaluated in the laboratory (about 10
).
ssbauer spectroscopyAgui, 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
Times Cited Count：4 Percentile：26.78(Materials Science, Multidisciplinary)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.
Konno, Chikara; Kato, Yoshinari*; Takakura, Kosuke; Ota, Masayuki; Ochiai, Kentaro; Sato, Satoshi
Progress in Nuclear Science and Technology (Internet), 4, p.606 - 609, 2014/04
At International Conference on Nuclear Data for Science and Technology in 2007 we pointed out that most of unresolved resonance data in JENDL-3.3 have a problem related to self-shielding correction. Here with a simple calculation model we investigated if the newest JENDL, JENDL-4.0, was improved for the problem or not. As a result, it seems that unresolved resonance data in JENDL-4.0 have no problem, but we are afraid that the self-shielding effect for the unresolved resonance data in JENDL-4.0 is too large. New integral experiments for unresolved resonance data are strongly recommended in order to verify unresolved resonance data.
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
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.
Mori, Takero; Araki, Kosuke*; Kato, Mitsuya*; Takano, Masahito*
no journal, ,
An improved analysis model and the actual component characteristic data for the main cooling system are incorporated in Monju plant dynamics analysis code: Super-COPD. The verification of this new analysis model is based on the results of a plant trip test at 40% rated power and on plant control system characteristics.
Kato, Masashi*; Fukushima, Keisuke*; Kasuga, Masanobu*; Kito, Kosuke*; Ichimura, Masaya*; Kanechika, Masakazu*; Ishiguro, Osamu*; Kachi, Tetsu*; Oshima, Takeshi
no journal, ,
no abstracts in English
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.
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.
Kato, Yoshinari; Ochiai, Kentaro; Takakura, Kosuke; Sato, Satoshi; Konno, Chikara
no journal, ,
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) As, Se, W: Calculation results with JENDL-4.0 agree with the measured ones better than those with JENDL-3.3. (2) CF, Si, Co, Mn, Cu, Ti, Mo, Zr: Calculation results with JENDL-4.0 are almost the same as those with JENDL-3.3. (3) Cr, Nb: Calculation results with JENDL-4.0 are partially better and partially worse than those with JENDL-3.3.
Kato, Yoshinari; Ochiai, Kentaro; Takakura, Kosuke; Sato, Satoshi; Konno, Chikara
no journal, ,
no abstracts in English
Konno, Chikara; Kato, Yoshinari; Takakura, Kosuke; Ota, Masayuki; Ochiai, Kentaro; Sato, Satoshi
no journal, ,
At International Conference on Nuclear Data for Science and Technology in 2007 we pointed out that most of unresolved resonance data in JENDL-3.3 have a problem related to self-shielding correction. Here with a simple calculation model we investigated if the newest JENDL, JENDL-4.0, was improved for the problem or not. As a result, it seems that unresolved resonance data in JENDL-4.0 have no problem, but we are afraid that the self-shielding effect for the unresolved resonance data in JENDL-4.0 is too large. New integral experiments for unresolved resonance data are strongly recommended in order to verify unresolved resonance data.
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.
Kato, Naoki*; Muta, Hiroaki*; Tanaka, Kosuke; Matsuda, Tetsushi*; Oishi, Yuji*; Kurosaki, Ken*; Yamanaka, Shinsuke*
no journal, ,
Physical properties of sintered UO specimens containing over 10% simulated MA were investigated. Based on the measured data, a prediction method for the properties was introduced.
Chikazawa, Yoshitaka; Aizawa, Kosuke; Kato, Atsushi; Eto, Masao*; Matsunaga, Shoko*
no journal, ,
A next generation sodium cooled reactor introduce a flexible arm fuel handling machine to reduce reactor vessel diameter. In this study, prevention of jamming at the movable parts of the fuel handling machine and recovery from jamming is investigated.
Tomita, Hideki*; Saito, Kosuke*; Ohashi, Masaya*; Sonnenschein, V.*; Kato, Kotaro*; Suzuki, So*; Iguchi, Tetsuo*; Morita, Masato*; Sakamoto, Tetsuo*; Kanenari, Keita*; et al.
no journal, ,
no abstracts in English
