Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Takahashi, Yoshio*; Miura, Hikaru*; Yamada, Shinya*; Sekizawa, Oki*; Nitta, Kiyofumi*; Hashimoto, Tadashi*; Yomogida, Takumi; Yamaguchi, Akiko; Okada, Shinji*; Itai, Takaaki*; et al.
Journal of Hazardous Materials, 495, p.139031_1 - 139031_19, 2025/09
In this presentation, we analyzed the chemical state of cesium in radiocesium-bearing microparticles (CsMPs) released during the 2011 Fukushima Daiichi Nuclear Power Plant accident using high-resolution X-ray absorption spectroscopy (XANES) and micro X-ray fluorescence (
-XRF). The results identified two forms of cesium: one dissolved in glass and the other enriched on the surfaces of internal voids. The latter is considered to have originally existed as a gas and became concentrated during the cooling and solidification of the molten glass. These findings are crucial for understanding the formation process of CsMPs during the accident, as well as for future decommissioning and safety assessments.
Yamada, Takatoshi*; Ogawa, Shuichi*; Yoshigoe, Akitaka; Tsuda, Yasutaka; Masuzawa, Tomoaki*; Okada, Mitsuhiro*; Kobashi, Kazufumi*; Okigawa, Yuki*
Japanese Journal of Applied Physics, 64(7), p.07SP17_1 - 07SP17_5, 2025/07
Times Cited Count：0 Percentile：0.00
neutron diffraction studyIto, Tatsuya; Ogawa, Yuhei*; Gong, W.; Mao, W.*; Kawasaki, Takuro; Okada, Kazuho*; Shibata, Akinobu*; Harjo, S.
Acta Materialia, 287, p.120767_1 - 120767_16, 2025/04
Times Cited Count：5 Percentile：95.31(Materials Science, Multidisciplinary)
neutron diffraction study to elucidate hydrogen effect on the deformation mechanism in Type 310S austenitic stainless steelIto, Tatsuya; Ogawa, Yuhei*; Gong, W.; Mao, W.*; Kawasaki, Takuro; Okada, Kazuho*; Shibata, Akinobu*; Harjo, S.
Proceedings of the 7th International Symposium on Steel Science (ISSS 2024), p.237 - 240, 2024/11
Cl on Cu oxide Surfaces; Cu
O(111) and bulk CuO precursor "29"; Structure on Cu(111)Hayashida, Koki*; Tsuda, Yasutaka; Murase, Natsumi*; Yamada, Takashi*; Yoshigoe, Akitaka; Di
o, W. A.*; Okada, Michio*
Applied Surface Science, 669, p.160475_1 - 160475_6, 2024/10
Times Cited Count：1 Percentile：21.93(Chemistry, Physical)Kato, Hiroyuki S.*; Muroyama, Mizuho*; Kobayakawa, Nano*; Muneyasu, Riku*; Tsuda, Yasutaka; Murase, Natsumi*; Watanabe, Seiya*; Yamada, Takashi*; Kanematsu, Yusuke*; Tachikawa, Masanori*; et al.
Journal of Physical Chemistry Letters (Internet), 15(43), p.10769 - 10776, 2024/10
Times Cited Count：2 Percentile：45.07(Chemistry, Physical)Nagoshi, Yasuto*; Fukahori, Takuya*; Okada, Hiroshi*; Takahashi, Akiyuki*; Shimodaira, Masaki; Ueda, Takashi*; Ogawa, Takuya*; Yashirodai, Kenji*; Takahashi, Yukio*; Ohata, Mitsuru*
Transactions of the 27th International Conference on Structural Mechanics in Reactor Technology (SMiRT 27) (Internet), 9 Pages, 2024/03
no abstracts in English
Cl dissociation, CH abstraction, and Cl adsorption from the dissociative scattering of supersonic CHCl on Cu(111) and Cu(410)Makino, Takamasa*; Tsuda, Yasutaka; Yoshigoe, Akitaka; Dio, W. A.*; Okada, Michio*
Applied Surface Science, 642, p.158568_1 - 158568_6, 2024/01
Times Cited Count：4 Percentile：40.94(Chemistry, Physical)Okada, Yuji; Magome, Hirokatsu; Matsui, Yoshinori
JAEA-Technology 2022-014, 113 Pages, 2022/09
JAEA-Technology-2022-014.pdf:15.79MB
Material irradiation test system had been newly installed in JMTR (Japan Materials Testing Reactor) with taking 5 years which was from 2008 through 2013. The aim of material irradiation test system is to conduct IASCC (Irradiation Assisted Stress Corrosion Cracking) evaluation study. This system is mainly consist of water control unit, which can simulate elevated temperature and pressure of the light water reactor environment in the reactor, and load control unit, which can perform the crack propagation examination under irradiation. This load control unit gives a load to CT (Compact Tension) specimen, and perform the crack propagation examination. The principle of loading to CT specimen is using pressure difference between pressure generated by high temperature and high pressure water by water control unit in capsule and pressure generated by load gas pressure supplied by helium gas cylinder in bellows installed in load control unit. In 2013, the commissioning of material irradiation test system was carried out for adjustment. During this commissioning, the correlation between the differential pressure in load control unit and the load was confirmed by using the test container connected to load control unit with load cell. From the results of commissioning, the problem, which the load change speeds at loading and unloading were different due to different pressure change speeds by the piping resistance performance in the periodic loading test in which load from minimum to maximum repeatedly applied, was confirmed. This report summarizes the problem of load change speed due to the piping resistance performance, which was confirmed in 2013, the improvement and performance test of load control unit for solving the problem described above, which were carried out from 2014 to 2015, and operating procedure.
Okada, Kazuho*; Shibata, Akinobu*; Gong, W.; Tsuji, Nobuhiro*
Acta Materialia, 225, p.117549_1 - 117549_13, 2022/02
Times Cited Count：33 Percentile：92.60(Materials Science, Multidisciplinary)Wada, Yuki*; Matsumoto, Takahiro*; Enoto, Teruaki*; Nakazawa, Kazuhiro*; Yuasa, Takayuki*; Furuta, Yoshihiro*; Yonetoku, Daisuke*; Sawano, Tatsuya*; Okada, Go*; Nanto, Hidehito*; et al.
Physical Review Research (Internet), 3(4), p.043117_1 - 043117_31, 2021/12
molecular adsorption on Cu(111); Copper oxidesHayashida, Koki*; Tsuda, Yasutaka; Yamada, Takashi*; Yoshigoe, Akitaka; Okada, Michio*
ACS Omega (Internet), 6(40), p.26814 - 26820, 2021/10
Times Cited Count：18 Percentile：64.19(Chemistry, Multidisciplinary)We report the X-ray photoemission spectroscopy (XPS) characterization of the bulk CuO(111) surface and 8-type and 29-type oxide structures on Cu(111) prepared by using 0.5 eV O supersonic molecular beam (SSMB) source. We propose a new structural model for the 8-type oxide structure and also confirmed the previously proposed model for the [29] oxide structure on Cu(111), based on the O1s XPS spectra. The detection-angle dependence of the O 1s spectra supports that the nanopyramidal model is more preferable for the (
X)R30
CuO(111). We also report the electronic excitations which O1s electrons suffer.
Okutsu, Kenichi*; Yamashita, Takuma*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.
Fusion Engineering and Design, 170, p.112712_1 - 112712_4, 2021/09
Times Cited Count：3 Percentile：28.57(Nuclear Science & Technology)A muonic molecule which consists of two hydrogen isotope nuclei (deuteron (d) or tritium (t)) and a muon decays immediately via nuclear fusion and the muon will be released as a recycling muon, and start to find another hydrogen isotope nucleus. The reaction cycle continues until the muon ends up its lifetime of 2.2 s. Since the muon does not participate in the nuclear reaction, the reaction is so called a muon catalyzed fusion (CF). The recycling muon has a particular kinetic energy (KE) of the muon molecular orbital when the nuclear reaction occurs. Since the KE is based on the unified atom limit where distance between two nuclei is zero. A precise few-body calculation estimating KE distribution (KED) is also in progress, which could be compared with the experimental results. In the present work, we observed recycling muons after CF reaction.
Yamashita, Takuma*; Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.
Fusion Engineering and Design, 169, p.112580_1 - 112580_5, 2021/08
Times Cited Count：3 Percentile：28.57(Nuclear Science & Technology)A muon () having 207 times larger mass of electron and the same charge as the electron has been known to catalyze a nuclear fusion between deuteron (d) and triton (t). These two nuclei are bound by and form a muonic hydrogen molecular ion, dt. Due to the short inter-nuclear distance of dt, the nuclear fusion, d +t
+ n + 17.6 MeV, occurs inside the molecule. This reaction is called muon catalyzed fusion (CF). Recently, the interest on CF is renewed from the viewpoint of applications, such as a source of high-resolution muon beam and mono-energetic neutron beam. In this work, we report a time evolution calculation of CF in a two-layered hydrogen isotope target.
Hirota, Takatoshi*; Nagoshi, Yasuto*; Hojo, Kiminobu*; Okada, Hiroshi*; Takahashi, Akiyuki*; Katsuyama, Jinya; Ueda, Takashi*; Ogawa, Takuya*; Yashirodai, Kenji*; Ohata, Mitsuru*; et al.
Proceedings of ASME 2021 Pressure Vessels and Piping Conference (PVP 2021) (Internet), 9 Pages, 2021/07
Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count：60 Percentile：95.74(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
O formation on CuPd(111) and CuPt(111)Tsuda, Yasutaka; Gueriba, J. S.*; Makino, Takamasa*; Dio, W. A.*; Yoshigoe, Akitaka; Okada, Michio*
Scientific Reports (Internet), 11, p.3906_1 - 3906_8, 2021/02
Times Cited Count：8 Percentile：27.72(Multidisciplinary Sciences)Nagae, Daisuke*; Abe, Yasushi*; Okada, Shunsuke*; Omika, Shuichiro*; Wakayama, Kiyoshi*; Hosoi, Shun*; Suzuki, Shinji*; Moriguchi, Tetsuro*; Amano, Masamichi*; Kamioka, Daiki*; et al.
Nuclear Instruments and Methods in Physics Research A, 986, p.164713_1 - 164713_7, 2021/01
Times Cited Count：11 Percentile：75.14(Instruments & Instrumentation)
dosimetry system based on an optical fiber-coupled microsized photostimulable phosphor for stereotactic body radiation therapyYada, Ryuichi*; Maenaka, Kazusuke*; Miyamoto, Shuji*; Okada, Go*; Sasakura, Aki*; Ashida, Motoi*; Adachi, Masashi*; Sato, Tatsuhiko; Wang, T.*; Akasaka, Hiroaki*; et al.
Medical Physics, 47(10), p.5235 - 5249, 2020/10
Times Cited Count：9 Percentile：47.90(Radiology, Nuclear Medicine & Medical Imaging)The dosimeter system is capable of real-time, accurate, and precise measurement under stereotactic body radiation therapy (SBRT) conditions. The probe is smaller than a conventional dosimeter, has excellent spatial resolution, and can be valuable in SBRT with a steep dose distribution over a small field. The developed PSP dosimeter system appears to be suitable for in vivo SBRT dosimetry.
Abe, Mitsushi*; Bae, S.*; Beer, G.*; Bunce, G.*; Choi, H.*; Choi, S.*; Chung, M.*; da Silva, W.*; Eidelman, S.*; Finger, M.*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2019(5), p.053C02_1 - 053C02_22, 2019/05
Times Cited Count：167 Percentile：99.36(Physics, Multidisciplinary)This paper introduces a new approach to measure the muon magnetic moment anomaly 
and the muon electric dipole moment (EDM) 
at the J-PARC muon facility. The goal of our experiment is to measure 
and using an independent method with a factor of 10 lower muon momentum, and a factor of 20 smaller diameter storage-ring solenoid compared with previous and ongoing muon g-2 experiments with unprecedented quality of the storage magnetic field. Additional significant differences from the present experimental method include a factor of 1000 smaller transverse emittance of the muon beam (reaccelerated thermal muon beam), its efficient vertical injection into the solenoid, and tracking each decay positron from muon decay to obtain its momentum vector. The precision goal for is a statistical uncertainty of 450 parts per billion (ppb), similar to the present experimental uncertainty, and a systematic uncertainty less than 70 ppb. The goal for EDM is a sensitivity of 
e
cm.
