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Journal Articles

Uplift and denudation history of the Akaishi Range, a thrust block formed by arc-arc collision in central Japan; Insights from low-temperature thermochronometry and thermokinematic modeling

Sueoka, Shigeru; Ikeda, Yasutaka*; Kano, Kenichi*; Tsutsumi, Hiroyuki*; Tagami, Takahiro*; Kohn, B. P.*; Hasebe, Noriko*; Tamura, Akihiro*; Arai, Shoji*; Shibata, Kenji*

Journal of Geophysical Research; Solid Earth, 122(8), p.6787 - 6810, 2017/08

no abstracts in English

Journal Articles

Thermal-hydraulics technological strategy roadmap that improves safety of LWRs

Arai, Kenji*; Umezawa, Shigemitsu*; Oikawa, Hirohide*; Onuki, Akira*; Nakamura, Hideo; Nishi, Yoshihisa*; Fujii, Tadashi*

Nihon Genshiryoku Gakkai-Shi ATOMO$$Sigma$$, 58(3), p.161 - 166, 2016/03

no abstracts in English

JAEA Reports

Proceedings of the 21st Meeting of the International Collaboration on Advanced Neutron Sources (ICANS-XXI); Sep. 29 - Oct.3, 2014, Ibaraki Prefectural Center, Mito, Japan

Oku, Takayuki; Nakamura, Mitsutaka; Sakai, Kenji; Teshigawara, Makoto; Hideki, Tatsumoto*; Yonemura, Masao*; Suzuki, Junichi*; Arai, Masatoshi*

JAEA-Conf 2015-002, 660 Pages, 2016/02


The twenty first meeting of the International Collaboration on Advanced Neutron Source (ICANS-XXI) was held at Ibaraki Prefectural Culture Center in Mito from 29 September to 3 October 2014. It was hosted by Japan Atomic Energy Agency (JAEA), High Energy Accelerator Research Organization (KEK) and Comprehensive Research Organization for Science and Society (CROSS). In the meeting, new science and technology in the new era with the high power neuron sources were discussed in mostly "workshop style" sessions. In each session, various kinds of issues related to not only the hardware, but also the software and even radiation safety were discussed with the keyword of "INTERFACE". More than 200 Papers were presented in the meeting and 72 contributed papers are compiled in the proceedings.

Journal Articles

Recent progress in the chopper spectrometer 4SEASONS at J-PARC

Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Ishikado, Motoyuki*; Nakajima, Kenji; Kawamura, Seiko; Nakatani, Takeshi; et al.

JAEA-Conf 2015-002, p.319 - 329, 2016/02

Journal Articles

Background caused by continuously emitted high-energy neutrons at the chopper spectrometer 4SEASONS

Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Ishikado, Motoyuki*; Nakajima, Kenji; Harada, Masahide; Arai, Masatoshi

JPS Conference Proceedings (Internet), 8, p.036001_1 - 036001_6, 2015/09

Journal Articles

Neutron scattering study of spin fluctuations in La$$_{2-x}$$Sr$$_{x}$$CuO$$_{4}$$ by four-dimensional mapping of neutron cross-sections using the 4SEASONS chopper spectrometer

Wakimoto, Shuichi; Ikeuchi, Kazuhiko*; Arai, Masatoshi; Fujita, Masaki*; Kajimoto, Ryoichi; Kawamura, Sho*; Matsuura, Masato*; Nakajima, Kenji; Yamada, Kazuyoshi*

JPS Conference Proceedings (Internet), 8, p.034013_1 - 034013_6, 2015/09

Journal Articles

Development status of the NMR system for the polarized $$^{3}$$He Neutron Spin Filter (NSF) in the MLF at J-PARC

Sakai, Kenji; Oku, Takayuki; Hayashida, Hirotoshi*; Kira, Hiroshi*; Hiroi, Kosuke; Ino, Takashi*; Oyama, Kenji*; Okawara, Manabu*; Kakurai, Kazuhisa; Shinohara, Takenao; et al.

JPS Conference Proceedings (Internet), 8, p.036015_1 - 036015_6, 2015/09

The polarized $$^{3}$$He filter, which polarizes neutrons due to a large neutron absorption cross section of $$^{3}$$He with strong spin selectivity, becomes a convenient neutron spin filter (NSF) because it is operated immediately after its installation in beam lines without any neutron beam adjustments. For realizing such the NSF, a nuclear magnetic resonance (NMR) system is indispensable for monitoring $$^{3}$$He nuclear spin polarization ${it P}$ of the NSF. We have developed the flexible NMR system based on adiabatic fast passage (AFP) and pulse NMR methods by using their complementary features. In comparing with the values of ${it P}$ obtained by neutron transmission measurement at the beam line 10 of the J-PARC, we measured the correlations between the AFP and pulse NMR signals as changing condition of temperature, amplitude and applying period of the radio frequency field for the pulse NMR, and so on. As the results, we confirmed that our system would function enough as the ${it P}$ monitor.

Journal Articles

New AESJ thermal-hydraulics roadmap for LWR safety improvement and development after Fukushima accident

Nakamura, Hideo; Arai, Kenji*; Oikawa, Hirohide*; Fujii, Tadashi*; Umezawa, Shigemitsu*; Abe, Yutaka*; Sugimoto, Jun*; Koshizuka, Seiichi*; Yamaguchi, Akira*

Proceedings of 16th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-16) (USB Flash Drive), p.5353 - 5366, 2015/08

Journal Articles

Uplift and denudation history of the Yoro-Suzuka-Nunobiki mountains based on apatite fission-track thermochronology

Sueoka, Shigeru; Tsutsumi, Hiroyuki*; Tagami, Takahiro*; Hasebe, Noriko*; Tamura, Akihiro*; Arai, Shoji*; Shibata, Kenji

Fisshion, Torakku Nyusureta, (27), p.17 - 19, 2014/12

We are attempting to reveal uplift/denudation history of the Yoro-Suzuka-Nunobiki mountains, southwest Japan, by using apatite fission-track (AFT) thermochronology. We obtained AFT ages of 47-30 Ma. The ages are younger in the central and southern part of the Suzuka Range and get older to the north and south. Inverse thermal modeling based on the AFT ages and lengths indicates the difference among the ages reflect amount of denudation accommodate with the mountains uplifting in the past few million years. These results imply the process of the mountain uplifting of this area is more complicated than the developments of the basins propagating from south to north.

Journal Articles

Structure and dynamics of solid electrolyte (LiI)$$_{0.3}$$(LiPO$$_{3}$$)$$_{0.7}$$

Kartini, E.*; Nakamura, Mitsutaka; Arai, Masatoshi; Inamura, Yasuhiro; Nakajima, Kenji; Maksum, T.*; Hoggowiranto, W.*; Putra, T. Y. S. P.*

Solid State Ionics, 262, p.833 - 836, 2014/09

 Times Cited Count:17 Percentile:59.3(Chemistry, Physical)

We present the neutron scattering study of superionic glass (LiI)$$_{0.3}$$(LiPO$$_{3}$$)$$_{0.7}$$ by using the inelastic neutron spectrometer AMATERAS at J-PARC. From the inelastic scattering, low energy excitation or the Boson Peak appears at $$sim$$ 6.5 meV. The extra quasielastic scattering was observed in the energy range 1 meV $$<$$ E $$<$$ 3 meV at 285 K but not at 20 K. The Q dependence of the dynamical structure factor S(Q,E) can be approximated to the long-wave acoustic like density fluctuation.

Journal Articles

Development of portable polarized $$^{3}$$He neutron spin filter and its application to magnetic field imaging at J-PARC

Sakai, Kenji; Oku, Takayuki; Hayashida, Hirotoshi; Kira, Hiroshi*; Shinohara, Takenao; Oikawa, Kenichi; Harada, Masahide; Kakurai, Kazuhisa; Aizawa, Kazuya; Arai, Masatoshi; et al.

Journal of Physics; Conference Series, 528, p.012016_1 - 012016_7, 2014/07

 Times Cited Count:2 Percentile:70.26

In polarized neutron experiments, it is interested in expanding measurable neutron energy region up to epithermal neutrons. For realizing this situation, a Polarized $$^{3}$$He Spin Flipper (PHSF) has a key role because it can polarize from cold to epithermal neutrons, and flip neutron spins by flipping the $$^{3}$$He nuclear spin direction. We have developed the portable PHSF consisting of a cylindrical glass cell filled with $$^{3}$$He gas which is installed a solenoid coil of 20 cm in diameter and 30 cm long. After polarizing the $$^{3}$$He gas by irradiating a laser light based on a SEOP technique, the PHSF is brought by hands to experimental areas with kept its polarization. We carried out the feasibility test on our portable PHSF in the MLF of J-PARC and demonstrated it worked well by evaluating flipping ratios of polarized neutrons and attempting to visualize magnetic fields generated by sample coils.

Journal Articles

Feasibility demonstration of a new Fermi chopper with supermirror-coated slit package

Nakamura, Mitsutaka; Kambara, Wataru; Krist, T.*; Shinohara, Takenao; Ikeuchi, Kazuhiko*; Arai, Masatoshi; Kajimoto, Ryoichi; Nakajima, Kenji; Tanaka, Hiromichi; Suzuki, Junichi*; et al.

Nuclear Instruments and Methods in Physics Research A, 737, p.142 - 147, 2014/02

 Times Cited Count:3 Percentile:27.75(Instruments & Instrumentation)

The efficiency of inelastic neutron scattering measurements using a chopper spectrometer can be markedly improved by utilizing multiple incident energies (Multi-Ei method). However, in conventional chopper systems, optimization of the experimental condition for all incident energies is absolutely impossible. We developed a new Fermi chopper with a supermirror-coated slit package in order to overcome the problem and experimentally demonstrated that the full optimization of the experimental condition for multiple incident energies is nearly achieved.

Journal Articles

Mode-distribution analysis of quasielastic neutron scattering and application to liquid water

Kikuchi, Tatsuya; Nakajima, Kenji; Kawamura, Seiko; Inamura, Yasuhiro; Yamamuro, Osamu*; Kofu, Maiko*; Kawakita, Yukinobu; Suzuya, Kentaro; Nakamura, Mitsutaka; Arai, Masatoshi

Physical Review E, 87(6), p.062314_1 - 062314_8, 2013/06

 Times Cited Count:13 Percentile:63.64(Physics, Fluids & Plasmas)

A quasi-elastic neutron scattering (QENS) experiment is a particular technique that endeavors to define a relationship between time and space for the diffusion dynamics of atoms and molecules. However, in most cases, analyses of QENS data are model dependent. We have developed a new method for processing QENS data without a specific model, wherein all modes can be described as combinations of the relaxations based on the exponential law. By this method, we can obtain a new distribution function, $$B(Q,Gamma)$$, which we call the mode distribution function (MDF), to represent the number of relaxation modes and distributions of the relaxation times in the modes. The deduction of MDF is based on the maximum entropy method. We report the first application to experimental data of liquid water. In addition to the two known modes, the existence of a new relaxation mode of water molecules with an intermediate time scale has been discovered.

Journal Articles

Recent developments of instruments in a spallation neutron source at J-PARC and those prospects in the future

Arai, Masatoshi; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Nakajima, Kenji; Shibata, Kaoru; Takahashi, Nobuaki; Suzuki, Junichi*; Takata, Shinichi; Yamada, Takeshi*; et al.

Journal of the Physical Society of Japan, 82(Suppl.A), p.SA024_1 - SA024_14, 2013/01

 Times Cited Count:6 Percentile:44.56(Physics, Multidisciplinary)

The paper describes developments of neutron scattering instruments in J-PARC neutron facility, which is a short pulse spallation source operated at a repetition rate 25 Hz and has a proton power 1 MW. New concept has been adopted to utilize high intensity coupled moderator even for a high resolution inelastic scattering instruments by taking a pulse shaping chopper system. Advanced technique has been also realized by taking an ability of event-recording system altogether with an improvement of a chopper system, realizing multi-Ei method. The paper also touches upon a general design concept for diffractometers in accordance with the source characteristics.

Journal Articles

Development of the process flow diagram of the pyrochemical reprocessing of spent nitride fuel for ADS

Sato, Takumi; Nishihara, Kenji; Hayashi, Hirokazu; Kurata, Masaki*; Arai, Yasuo

Proceedings of 11th OECD/NEA Information Exchange Meeting on Actinide and Fission Product Partitioning and Transmutation (Internet), 9 Pages, 2012/00

Nitride fuel cycle for transmutation of long-lived minor actinides (MAs) has been developed in Japan Atomic Energy Agency (JAEA) under the double-strata nuclear fuel cycle concept. This study aims at developing the process flow diagram with the material balance sheet of the pyrochemical reprocessing of spent nitride fuel for ADS to evaluate the technological feasibility of the fuel cycle. Three process flow diagrams were proposed in this work: (1) the currently-proposed process with the molten salt electrorefining of spent nitride fuel, (2) the process with the molten salt electrorefining of the actinide-cadmium alloy after the chemical dissolution of spent nitride fuel, and, (3) the process combining the chemical dissolution of spent nitride fuel and the multi-stage counter current extraction. Moreover, the material balance was evaluated for the process (1) by use of the calculated and experimental data of the nitride fuel for ADS.

Journal Articles

Repetition Rate Multiplication: RRM, an advanced measuring method planed for the backscattering instrument, ${it DNA}$ at the MLF, J-PARC

Takahashi, Nobuaki; Shibata, Kaoru; Kawakita, Yukinobu; Nakajima, Kenji; Inamura, Yasuhiro; Nakatani, Takeshi; Nakagawa, Hiroshi; Fujiwara, Satoru; Sato, Taku*; Tsukushi, Itaru*; et al.

Journal of the Physical Society of Japan, 80(Suppl.B), p.SB007_1 - SB007_4, 2011/12

 Times Cited Count:6 Percentile:44.2(Physics, Multidisciplinary)

Journal Articles

Development of the pyrochemical process of spent nitride fuels for ADS; Its elemental technologies and process flow diagram

Hayashi, Hirokazu; Sato, Takumi; Shibata, Hiroki; Iwai, Takashi; Nishihara, Kenji; Arai, Yasuo

Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 6 Pages, 2011/12

R&D on the transmutation of long-lived minor actinides (MA) by the accelerator-driven system (ADS) using nitride fuels is underway at Japan Atomic Energy Agency. In regard to reprocessing technology, pyrochemical process has several advantages in case of treating spent fuel with large decay heat and fast neutron emission, and recovering highly enriched N-15. In the pyrochemical reprocessing, plutonium (Pu) and MA are dissolved in LiCl-KCl eutectic melts and selectively recovered into liquid cadmium (Cd) cathode by molten salt electrorefining. The recovered Pu and MA are converted to nitrides by the nitridation-distillation combined method, in which the Cd alloys containing Pu and MA are heated in nitrogen gas stream. The authors have investigated its elemental technologies such as electrorefining and renitridation. On the other hand, development of the process flow diagram with the material balance sheet of the pyrochemical reprocessing of spent nitride fuel for ADS is in progress. This paper summarized recent progress of the study which aims to prove the technological applicability of pyrochemical process to the nitride fuel cycle for transmutation of MA.

Journal Articles

Quantitative magnetic field imaging by polarized pulsed neutrons at J-PARC

Shinohara, Takenao; Sakai, Kenji; Oi, Motoki; Kai, Tetsuya; Harada, Masahide; Oikawa, Kenichi; Maekawa, Fujio; Suzuki, Junichi; Oku, Takayuki; Takata, Shinichi; et al.

Nuclear Instruments and Methods in Physics Research A, 651(1), p.121 - 125, 2011/09

 Times Cited Count:26 Percentile:88.13(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Developments of in-situ SEOP polarized $$^{3}$$He neutron spin filter in Japan

Kira, Hiroshi; Sakaguchi, Yoshifumi; Oku, Takayuki; Suzuki, Junichi; Nakamura, Mitsutaka; Arai, Masatoshi; Endo, Yasuo; Chang, L.-J.; Kakurai, Kazuhisa; Arimoto, Yasushi*; et al.

Journal of Physics; Conference Series, 294, p.012014_1 - 012014_5, 2011/06

 Times Cited Count:11 Percentile:94.8

Journal Articles

Applications of $$^{3}$$He neutron spin filters on the small-angle neutron scattering spectrometer SANS-J-II

Sakaguchi, Yoshifumi; Kira, Hiroshi; Oku, Takayuki; Shinohara, Takenao; Suzuki, Junichi; Sakai, Kenji; Nakamura, Mitsutaka; Aizawa, Kazuya; Arai, Masatoshi; Noda, Yohei; et al.

Journal of Physics; Conference Series, 294(1), p.012017_1 - 012017_7, 2011/06

 Times Cited Count:2 Percentile:66.21

247 (Records 1-20 displayed on this page)