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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：5 Percentile：87.42(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.
Wakui, Takashi; Yamasaki, Kazuhiko*; Futakawa, Masatoshi
Advanced Experimental Mechanics, 7, p.103 - 109, 2022/08
As part of the development of technique to cut and reduce the volume of highly radioactive components in the closed space, pulsed Nd:YAG laser was irradiated to radiation shielding glasses with the different lead content in the different irradiation condition; power and number of irradiation. The large black irradiated area with concave shape and cracks around it occurred with an increase of the lead content, power and number of irradiation. General mechanical properties in unirradiated and irradiated area were investigated to investigate the influence of mechanical properties on the irradiation damage. The thermal impact fracture toughness calculated based on the estimated mechanical properties decreased with increasing the lead content. The micro hardness in black irradiated area was 10% smaller than that in the unirradiated area. The change of the mechanical property due to the laser irradiation was confirmed.
Wakui, Takashi; Yamasaki, Kazuhiko*; Futakawa, Masatoshi
Jikken Rikigaku, 22(2), p.96 - 104, 2022/06
Pulsed laser irradiation and indentation tests on radiation shielding glasses and a lead-free glass were carried out. The size of irradiation damage of the glass with high lead content was larger than that with low content. The micro plastic behavior of glasses was quantitatively determined using the inverse analyses based on indentation results. Flow stress decreased with an increase of lead content and that in irradiated area was lower than that in unirradiated area. On the other hand, plastic flow resistance increased with an increase of the lead content and that in irradiated area was higher than that in unirradiated area. Fracture energy and critical size of plastic zone around tip of crack in unirradiated and irradiated areas were calculated based on experimental results including constants evaluated using the inverse analysis. These values decreased with an increase of the lead content and these values in irradiated area were lower than that in unirradiated area.
Yamasaki, Kazuhiko*; Kato, Hironori*; Futakawa, Masatoshi; Teshigawara, Makoto
Jikken Rikigaku, 21(4), p.308 - 313, 2021/12
In this study, coloration and damage of radiation-resistant lead glasses by nanosecond pulse laser with visible wavelength are evaluated. Three kinds of radiation resistance glasses with different lead content: PbO-55 wt%, 71 wt% and PbO free glass are used. As a result, the transitional coloration and damage formation with phase differences had observed by nanosecond pulsed laser irradiation at peak power of 1 kW. Although high-lead concentration glass has lower thresholds for coloration in laser intensity, damage-formation thresholds for both PbO glasses were almost the same. On the other hand, no change was observed after laser-irradiation to PbO-free glass. In addition, photochemical and thermal reaction of PbO by nanosecond pulsed laser irradiation is considered from the result of intensity change at wave numbers 200-500
and 1000 cm in Raman spectrums.
Maruyama, Ryuji; Yamazaki, Dai; Aoki, Hiroyuki; Akutsu, Kazuhiro*; Hanashima, Takayasu*; Miyata, Noboru*; Soyama, Kazuhiko; Bigault, T.*; Saerbeck, T.*; Courtois, P.*
Journal of Applied Physics, 130(8), p.083904_1 - 083904_10, 2021/08
Times Cited Count：3 Percentile：26.56(Physics, Applied)Yamakawa, Koki*; Saruta, Masaaki*; Moritani, Hiroshi*; Yamazaki, Hiroaki*; Nishida, Akemi; Kawata, Manabu; Iigaki, Kazuhiko
Proceedings of 28th International Conference on Nuclear Engineering (ICONE 28) (Internet), 6 Pages, 2021/08
Several large-scale earthquakes have occurred, such as the Niigataken Chuetsu-oki Earthquake in 2007 and the 2011 off-the-Pacific coast of Tohoku Earthquake. Therefore, a three-dimensional (3D) finite element model to evaluate the local response of the reactor building is currently being developed for seismic response analysis. In order to refine the 3D finite element model, it is important to verify the correspondence to the seismic observation behaviors. In this study, the authors analyze the basic response characteristics, such as the natural frequencies and modes of the reactor building, and evaluate the effects of the amplitude of the seismic excitation on the response characteristics based on seismic observation records. This is done to clarify the behavior of a reactor building during earthquakes. These analyses will assist in quantitatively evaluating the correlation between the natural frequency of the building and the amplitude of the seismic excitation. Furthermore, the ratios of rotational displacement and displacement caused by building deformation for natural modes are discussed.
Sakakibara, Hiroshi; Aoki, Nobuhiro; Muto, Masahiro; Otabe, Jun; Takahashi, Kenji*; Fujita, Naoyuki*; Hiyama, Kazuhiko*; Suzuki, Hirokazu*; Kamogawa, Toshiyuki*; Yokosuka, Toru*; et al.
JAEA-Technology 2020-020, 73 Pages, 2021/03
JAEA-Technology-2020-020.pdf:8.26MB
The decommissioning is currently in progress at the prototype fast breeder reactor Monju. Fuel assemblies will be taken out of its core for the first step of the great task. Fuel assemblies stand on their own spike plugged into a socket on the core support plate and support with adjacent assemblies through their housing pads each other, resulting in steady core structure. For this reason, some substitutive assemblies are necessary for the purpose of discharging the fuel assemblies of the core. Monju side commissioned, therefore, Plutonium Fuel Development Center to manufacture the substitutive assemblies and the Center accepted it. This report gives descriptions of design, manufacture, and shipment in regard to the substitutive assemblies.
Maruyama, Ryuji; Yamazaki, Dai; Akutsu, Kazuhiro*; Hanashima, Takayasu*; Miyata, Noboru*; Aoki, Hiroyuki; Soyama, Kazuhiko
JPS Conference Proceedings (Internet), 33, p.011092_1 - 011092_6, 2021/03
no abstracts in English
Akutsu, Kazuhiro*; Kira, Hiroshi*; Miyata, Noboru*; Hanashima, Takayasu*; Miyazaki, Tsukasa*; Kasai, Satoshi*; Yamazaki, Dai; Soyama, Kazuhiko; Aoki, Hiroyuki
Polymers (Internet), 12(10), p.2180_1 - 2180_10, 2020/10
Times Cited Count：2 Percentile：6.78(Polymer Science)Naoe, Takashi; Teshigawara, Makoto; Futakawa, Masatoshi; Mizutani, Haruki; Muramatsu, Toshiharu; Yamada, Tomonori; Ushitsuka, Yuji*; Tanaka, Nobuatsu*; Yamasaki, Kazuhiko*
Proceedings of 8th International Congress on Laser Advanced Materials Processing (LAMP 2019) (Internet), 5 Pages, 2019/05
Laser cutting is one of the options in the disposal of radio-active waste, such as spallation neutron target vessel in J-PARC, etc. Due to unique characteristic of laser, such as non-contact system, it is more easily to provide remote-controlled system in comparison with conventional one, such as mechanical cutting machine, etc. However, a demerit of laser cutting is the sputter and fume caused by laser cutting, resulting in contamination with radio-active materials its surroundings. Recently it was developed that the spatter suppression technique by controlling laser beam profile in laser welding process. In order to apply this suppression technique to laser cutting, first of all, we attempted to observe the phenomenon at melting area during laser cutting using a high-speed video camera in order to make the physical model. The result showed that the appearance of fume and sputter were independently confirmed in the time evolution.
Shimazaki, Yosuke; Yamazaki, Kazunori; Iigaki, Kazuhiko
Hozengaku, 18(1), p.16 - 20, 2019/04
no abstracts in English
Maruyama, Ryuji; Yamazaki, Dai; Soyama, Kazuhiko
JPS Conference Proceedings (Internet), 22, p.011011_1 - 011011_5, 2018/11
Neutron multilayer mirrors are one of the most important optical elements for neutron scattering experiments. Good interface quality in terms of sharpness and smoothness plays a critical role in determining the performance of optical elements. We have shown that a multilayer with a large vertical correlation length and small lateral correlation length effectively suppresses the diffuse scattering intensity. In this study, the effect of the interface roughness correlation on the neutron reflectivity of the multilayer mirror is investigated using the reflectivity calculation based on the distorted wave Born approximation.
Maruyama, Ryuji; Yamazaki, Dai; Akutsu, Kazuhiro*; Hanashima, Takayasu*; Miyata, Noboru*; Aoki, Hiroyuki; Takeda, Masayasu; Soyama, Kazuhiko
Nuclear Instruments and Methods in Physics Research A, 888, p.70 - 78, 2018/04
Times Cited Count：4 Percentile：29.78(Instruments & Instrumentation)The multilayer structure of Fe/Si and Fe/Ge systems fabricated by ion beam sputtering (IBS) was investigated using X-ray and polarized neutron reflectivity measurements and scanning transmission electron microscopy with energy-dispersive X-ray analysis. The obtained result revealed that the incorporation of sputtering gas particles (Ar) in the Ge layer gives rise to a marked reduction in the neutron scattering length density (SLD) and contributes to the SLD contrast between the Fe and Ge layers almost vanishing for spin-down neutrons. This leads to a possibility of fine-tuning of the SLD for the IBS, which is required to realize a high polarization efficiency of a neutron polarizing supermirror. Fe/Ge polarizing supermirror with 
fabricated showed a spin-up reflectivity of 0.70 at the critical momentum transfer. The polarization was higher than 0.985 for the 
range where the correction for the polarization inefficiencies of the beamline works properly.
Nakajima, Kenji; Kawakita, Yukinobu; Ito, Shinichi*; Abe, Jun*; Aizawa, Kazuya; Aoki, Hiroyuki; Endo, Hitoshi*; Fujita, Masaki*; Funakoshi, Kenichi*; Gong, W.*; et al.
Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12
The neutron instruments suite, installed at the spallation neutron source of the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), is reviewed. MLF has 23 neutron beam ports and 21 instruments are in operation for user programs or are under commissioning. A unique and challenging instrumental suite in MLF has been realized via combination of a high-performance neutron source, optimized for neutron scattering, and unique instruments using cutting-edge technologies. All instruments are/will serve in world-leading investigations in a broad range of fields, from fundamental physics to industrial applications. In this review, overviews, characteristic features, and typical applications of the individual instruments are mentioned.
Yamazaki, Takumi; Takada, Chie; Tsujimura, Norio; Okada, Kazuhiko
Hoken Butsuri, 52(3), p.167 - 170, 2017/09
At the JAEA MOX Fuel Facilities, a worker engaged in glove box operations uses two personal dosemeters, one worn on the trunk under a protective apron and the other at the collar over the apron. The recorded lens of the eye dose is based on the photon dose measured by the collar dosemeter plus the neutron dose measured by the under-apron dosemeter.
Sakasai, Kaoru; Sato, Setsuo*; Seya, Tomohiro*; Nakamura, Tatsuya; To, Kentaro; Yamagishi, Hideshi*; Soyama, Kazuhiko; Yamazaki, Dai; Maruyama, Ryuji; Oku, Takayuki; et al.
Quantum Beam Science (Internet), 1(2), p.10_1 - 10_35, 2017/09
Neutron devices such as neutron detectors, optical devices including supermirror devices and 
He neutron spin filters, and choppers are successfully developed and installed at the Materials Life Science Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC), Tokai, Japan. Four software components of MLF computational environment, instrument control, data acquisition, data analysis, and a database, have been developed and equipped at MLF. MLF also provides a wide variety of sample environment options including high and low temperatures, high magnetic fields, and high pressures. This paper describes the current status of neutron devices, computational and sample environments at MLF.
Maruyama, Ryuji; Bigault, T.*; Wildes, A. R.*; Dewhurst, C. D.*; Saerbeck, T.*; Honecker, D.*; Yamazaki, Dai; Soyama, Kazuhiko; Courtois, P.*
Journal of Physics; Conference Series, 862(1), p.012017_1 - 012017_6, 2017/06
Times Cited Count：6 Percentile：90.11(Physics, Multidisciplinary)The in-plane magnetic structure of Fe/Si multilayers with a polycrystalline grain size less than the ferromagnetic exchange length was investigated using polarized neutron off-specular scattering and grazing-incidence small-angle scattering measurements. These complementary measurements, each of them covering different length scales, together with the data analysis based on the distorted wave Born approximation, revealed lateral correlation in the fluctuating orientation of the magnetization in the layer on a sub-
m length scale. The obtained in-plane magnetic structure is consistent with the random anisotropy model, i.e. competition between the exchange interactions between neighboring spins and the local magnetocrystalline anisotropy.
S
/Ag/Si substrateSakaguchi, Yoshifumi*; Asaoka, Hidehito; Uozumi, Yuki; Kondo, Keietsu; Yamazaki, Dai; Soyama, Kazuhiko; Ailavajhala, M.*; Mitkova, M.*
Journal of Applied Physics, 120(5), p.055103_1 - 055103_10, 2016/08
Times Cited Count：11 Percentile：46.66(Physics, Applied)Sakaguchi, Yoshifumi*; Asaoka, Hidehito; Uozumi, Yuki; Kawakita, Yukinobu; Ito, Takayoshi*; Kubota, Masato; Yamazaki, Dai; Soyama, Kazuhiko; Sheoran, G.*; Mitkova, M.*
Physica Status Solidi (A), 213(7), p.1894 - 1903, 2016/07
Times Cited Count：7 Percentile：33.84(Materials Science, Multidisciplinary)no abstracts in English
Sakaguchi, Yoshifumi*; Asaoka, Hidehito; Uozumi, Yuki; Kawakita, Yukinobu; Ito, Takayoshi*; Kubota, Masato; Yamazaki, Dai; Soyama, Kazuhiko; Ailavajhala, M.*; Wolf, K.*; et al.
JPS Conference Proceedings (Internet), 8, p.031023_1 - 031023_6, 2015/09
We report recent results of time-resolved neutron reflectivity measurements for silver photo-diffusion into Ge
S
(x=0.20, 0.33, 0.40) films performed on BL17 (SHARAKU). It is well known that silver diffuses into Ge-chalcogenide layer by visible light exposure with a distinct diffusion front, where the silver concentration abruptly drops off. Using an event recording system at the Materials and Life Science Experimental Facility, neutron reflectivity profiles were collected with a time-resolution of 30 seconds in the shortest case. It was found from the measurements that a relatively stable Ag-rich phase in the reaction layer is firstly formed, and then, slower diffusion occurs at the interface between Ag-rich and Ag-poor layers. Fourier transform analysis showed that the position of the interface is essentially fixed. This result is in contrast to the previously reported model of silver diffusion that postulates a mechanism involving progression of the diffusion front. The results of the measurements on Ag/Ge-Se films performed on the INTER instrument at ISIS are also reported.
