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Journal Articles

Petrography and geochronology of the Kuki granite, Kitakami mountains, northeastern Japan; Shallow crustal intrusion and emplacement processes of granitic magma

Suzuki, Satoshi*; Yuguchi, Takashi*; Ishiguro, Keito*; Endo, Kyoka*; Kato, Asuka*; Yokoyama, Kosuke*; Ogita, Yasuhiro; Yokoyama, Tatsunori; Sakata, Shuhei*; Ono, Takeshi*; et al.

Journal of Mineralogical and Petrological Sciences (Internet), 119(1), p.230807_1 - 230807_18, 2024/02

 Times Cited Count:1 Percentile:45.39(Mineralogy)

Understanding the crustal evolutionary dynamics of island arc-trench systems requires a thorough evaluation of magma chamber processes, and especially of shallow crustal granitic magma intrusion and emplacement processes. To address this, we studied the petrography and geochronology of the Kuki granite, Kitakami Mountains, northeast Japan, as an example of a non-adakitic granite at the magmatic flare-up stage. Granitic borehole samples reflect vertical variation within a magma chamber. Whole-rock chemical composition and mode data reveal a vertical transition from felsic to mafic composition with increasing depth, potentially due to gravitational fractionation of crystals in the magma chamber. The pressure and temperature history of the Kuki granite indicates no change in the magma depth with cooling from 800 to 730$$^{circ}$$C, and geobarometric calculations indicate the emplacement of magma at a depth of approximately10 km. Simultaneous determination of the zircon U Pb age, Ti concentration, and Th/U yields 1) the time temperature history of granitic magma before its solidification, and 2) the correlation between temperature and Th/U in the magma. The magma chamber cooled from ca. 900 to 700$$^{circ}$$C at approximately 125 Ma. The change in Th/U with temperature indicates greater fractional crystallization in the magma chamber at temperatures above 800$$^{circ}$$C than below 800$$^{circ}$$C. Samples from different depth exhibit common tendencies in terms of the relationship between Th/U and temperature, indicating the same system of fractional crystallization throughout the cooling magma chamber.

Journal Articles

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

 Times Cited Count:7 Percentile:73.20(Nuclear Science & Technology)

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.

Journal Articles

Sodium-cooled Fast Reactors

Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.

Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07

This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.

Journal Articles

Sm valence determination of Sm-based intermetallics using $$^{149}$$Sm M$"{o}$ssbauer and Sm L$$_{rm III}$$-edge X-ray absorption spectroscopies

Tsutsui, Satoshi; Higashinaka, Ryuji*; Nakamura, Raito*; Fujiwara, Kosuke*; Nakamura, Jin*; Kobayashi, Yoshio*; Ito, Takashi; Yoda, Yoshitaka*; Kato, Kazuo*; Nitta, Kiyofumi*; et al.

Hyperfine Interactions, 242(1), p.32_1 - 32_10, 2021/12

 Times Cited Count:1 Percentile:75.14(Physics, Atomic, Molecular & Chemical)

Journal Articles

Visualizing cation vacancies in Ce:Gd$$_{3}$$Al$$_{2}$$Ga$$_{3}$$O$$_{12}$$ 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

 Times Cited Count:6 Percentile:29.86(Physics, Applied)

To clarify the existence of cation vacancies in Ce-doped Gd$$_{3}$$Al$$_{2}$$Ga$$_{3}$$O$$_{12}$$ (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:Y$$_{3}$$Al$$_{5}$$O$$_{12}$$, 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$$^{2+}$$ ions at Al/Ga sites with oxygen vacancies, which resulted in the formation of vacancy clusters.

Journal Articles

Post-irradiation examinations of annular mixed oxide fuels with average burnup 4 and 5% FIMA

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:10 Percentile:68.22(Materials Science, Multidisciplinary)

Journal Articles

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

 Times Cited Count:3 Percentile:25.69(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$$_{2}$$ 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.

Journal Articles

Isotope-selective microscale imaging of radioactive Cs without isobaric interferences using sputtered neutral mass spectrometry with two-step resonant ionization employing newly-developed Ti:Sapphire lasers

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:10 Percentile:33.86(Chemistry, Analytical)

Journal Articles

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

 Times Cited Count:14 Percentile:64.78(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.

Journal Articles

Field test around Fukushima Daiichi Nuclear Power Plant site using improved Ce:Gd$$_{3}$$(Al,Ga)$$_{5}$$O$$_{12}$$ scintillator Compton camera mounted on an unmanned helicopter

Shikaze, 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:41 Percentile:96.07(Nuclear Science & Technology)

The Compton camera was improved for use with the unmanned helicopter. Increase of the scintillator array from 4$$times$$4 to 8$$times$$8 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 $$times$$ 60 m and 65 m $$times$$ 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 $$gamma$$-ray images including the hot spots were obtained with the angular resolution same as that evaluated in the laboratory (about 10$$^{circ}$$).

Journal Articles

The Study of the magnetization process of Fe film by magnetic Compton scattering and M$"o$ssbauer 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

 Times Cited Count:6 Percentile:23.79(Materials Science, Multidisciplinary)

We investigated the magnetization process of Fe (110) film using the field dependence of magnetic Compton scattering and M$"o$ssbauer spectroscopy. From the magnetic Compton profiles, the spin and orbital magnetic moment specific magnetization versus magnetizing field curves were obtained. From the M$"o$ssbauer 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.

Journal Articles

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

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$$_{2}$$, 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$$_{2}$$, 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.

Journal Articles

Self-shielding effect of unresolved resonance data in JENDL-4.0

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.

Oral presentation

Development of gamma-ray induced positron annihilation lifetime spectroscopy

Taira, Yoshitaka*; Fujimoto, Masaki*; Fujimori, Kosuke*; Kitaura, Mamoru*; Zen, H.*; Okano, Yasuaki*; Hosaka, Masahito*; Yamazaki, Junichiro*; Kato, Masahiro*; Hirade, Tetsuya; et al.

no journal, , 

For general positron sources, radioisotopes such as $$^{22}$$Na are often used. However, there is a problem that positrons cannot probe the deep region of metal materials with a thickness of 1 mm or more. Gamma-ray induced positron annihilation lifetime measurement (GiPALS) is a method for generating positrons in bulk samples with a thickness of several centimeters and samples placed in vessels such as high temperature and/or pressure furnaces. The annihilation lifetime of positrons is about 200 ps for metal materials, so it is important to use gamma rays with a shorter pulse width for GiPALS in order to accurately measure the positron lifetime. We have succeeded in the proof-of-principle experiment for GiPALS of ultra-short pulse gamma rays with a pulse width of 2 ps, which was originally developed using 90$$^{circ}$$ collision laser Compton scattering at UVSOR.

Oral presentation

Development of gamma-ray induced positron annihilation lifetime spectroscopy at UVSOR

Taira, Yoshitaka*; Fujimoto, Masaki*; Fujimori, Kosuke*; Kitaura, Mamoru*; Zen, H.*; Okano, Yasuaki*; Hosaka, Masahito*; Yamazaki, Junichiro*; Kato, Masahiro*; Hirade, Tetsuya; et al.

no journal, , 

For general positron sources, radioisotopes such as $$^{22}$$Na are often used. However, there is a problem that positrons cannot probe the deep region of metal materials with a thickness of 1 mm or more. Gamma-ray induced positron annihilation lifetime measurement (GiPALS) is a method for generating positrons in bulk samples with a thickness of several centimeters and samples placed in vessels such as high temperature and/or pressure furnaces. The annihilation lifetime of positrons is about 200 ps for metal materials, so it is important to use gamma rays with a shorter pulse width for GiPALS in order to accurately measure the positron lifetime. We have succeeded in the proof-of-principle experiment for GiPALS of ultra-short pulse gamma rays with a pulse width of 2 ps, which was originally developed using 90$$^{circ}$$ collision laser Compton scattering at UVSOR.

Oral presentation

Study for solidified products preparation conditions in sintering solidification technique of chabazite type zeolites

Naito, Ryo*; Kato, Fumihiro*; Arai, Tsuyoshi*; Usui, Akane; Onishi, Takashi; Tanaka, Kosuke; Matsukura, Minoru*; Mimura, Hitoshi*

no journal, , 

no abstracts in English

Oral presentation

Solvent extraction characteristics of europium and separation and recovery by extraction chromatography using new extractants

Otsu, Kosuke*; Kato, Chizu*; Ikeno, Masaya*; Saiga, Chuya*; Nihei, Yuya*; Fukutani, Satoshi*; Matsumura, Tatsuro; Fujii, Toshiyuki*

no journal, , 

no abstracts in English

Oral presentation

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

Oral presentation

Petrography and geochronology of the Kuki granite, Kitakami Mountains, northeastern Japan; Shallow crustal intrusion and emplacement processes of granitic magma

Suzuki, Satoshi*; Yuguchi, Takashi*; Ishiguro, Keito*; Endo, Kyoka*; Kato, Asuka*; Yokoyama, Kosuke*; Ogita, Yasuhiro; Yokoyama, Tatsunori; Sakata, Shuhei*; Ono, Takeshi*; et al.

no journal, , 

no abstracts in English

Oral presentation

Self-shielding effects of unresolved resonance data in JENDL-4.0

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.

31 (Records 1-20 displayed on this page)