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Omer, M.; Shizuma, Toshiyuki*; Koizumi, Mitsuo; Hajima, Ryoichi*; Hashimoto, Satoshi*; Miyamoto, Shuji*
LASTI Annual Report, 24, p.20 - 22, 2023/12
Oka, Hiroshi*; Tanno, Takashi; Yano, Yasuhide; Otsuka, Satoshi; Kaito, Takeji; Hashimoto, Naoyuki*
Journal of Nuclear Materials, 572, p.154032_1 - 154032_8, 2022/12
Times Cited Count:3 Percentile:66.21(Materials Science, Multidisciplinary)9Cr oxide dispersion strengthened steels with slightly different nitrogen concentrations (0.0034 - 0.029 wt%) were prepared and their creep property at 973 K was investigated with microstructural characterization before and after the creep test. The creep strength decreased significantly as the nitrogen concentration increased. Microstructural observation revealed that, in the higher nitrogen concentration specimen, coarse Y-rich inclusions were found along the boundary between transformed ferrite region and residual ferrite region. The solubility difference of nitrogen in and phase would induce the localized increment of nitrogen concentration in the boundary region during the austenitizing process, resulting in the thermodynamic destabilization and subsequent coarsening of the dispersed oxide particles. The rows of creep voids were found near the rupture part of the crept specimen, suggesting that the coarse inclusions were the starting point of creep void formation and the subsequent premature fracture.
Murase, Kiyoka*; Kataoka, Ryuho*; Nishiyama, Takanori*; Nishimura, Koji*; Hashimoto, Taishi*; Tanaka, Yoshimasa*; Kadokura, Akira*; Tomikawa, Yoshihiro*; Tsutsumi, Masaki*; Ogawa, Yasunobu*; et al.
Journal of Space Weather and Space Climate (Internet), 12, p.18_1 - 18_16, 2022/06
Times Cited Count:1 Percentile:20.65(Astronomy & Astrophysics)We identified two energetic electron precipitation (EEP) events during the growth phase of moderate substorms and estimated the mesospheric ionization rate for an EEP event for which the most comprehensive dataset from ground-based and space-born instruments was available. The mesospheric ionization signature reached below 70 km altitude and continued for ~15 min until the substorm onset, as observed by the PANSY radar and imaging riometer at Syowa Station in the Antarctic region. We also used energetic electron flux observed by the Arase and POES 15 satellites as the input for the air-shower simulation code PHITS to quantitatively estimate the mesospheric ionization rate. Combining the cutting-edge observations and simulations, we shed new light on the space weather impact of the EEP events during geomagnetically quiet times, which is important to understand the possible link between the space environment and climate.
Watanabe, Yuki; Tsuji, Tomoya; Hirota, Seiko*; Hokama, Tomonori; Nakajima, Junya; Tsujiguchi, Takakiyo*; Kimura, Tatsuki*; Koike, Hiromi*; Nakamura, Kaori*; Kuwata, Haruka*; et al.
Hoken Butsuri (Internet), 57(1), p.54 - 64, 2022/03
no abstracts in English
Tsukada, Kazuaki; Nagai, Yasuki*; Hashimoto, Shintaro; Minato, Futoshi; Kawabata, Masako*; Hatsukawa, Yuichi*; Hashimoto, Kazuyuki*; Watanabe, Satoshi*; Saeki, Hideya*; Motoishi, Shoji*
Journal of the Physical Society of Japan, 89(3), p.034201_1 - 034201_7, 2020/03
Times Cited Count:2 Percentile:21.72(Physics, Multidisciplinary)We found anomalously large yields of Ga, Ga, Zn and Cu by neutron irradiation on a ZnO sample in a polyethylene shield. Neutron beams are generated from the Be() reaction for 50 MeV deuterons. The yields obtained were more than 20 times larger than those in the unshielded sample. On the other hand, the yields of Ga, Ga, Zn and Cu from a metallic Zn sample and the yields of Cu, Ni and Zn from the ZnO and Zn samples were almost insensitive to the shield conditions. This finding would provide us a unique capability of accelerator neutrons to simultaneously produce a large amount of several radioisotopes, including proton induced reaction products, by using a single sample. The experimental data were compared with the yields estimated by using the Particle and Heavy Ion Transport code System and the result was discussed.
Ramos, R.*; Hioki, Tomosato*; Hashimoto, Yusuke*; Kikkawa, Takashi*; Frey, P.*; Kreil, A. J. E.*; Vasyuchka, V. I.*; Serga, A. A.*; Hillebrands, B.*; Saito, Eiji
Nature Communications (Internet), 10, p.5162_1 - 5162_8, 2019/11
Times Cited Count:24 Percentile:76.4(Multidisciplinary Sciences)Pyeon, C. H.*; Yamanaka, Masao*; Oizumi, Akito; Fukushima, Masahiro; Chiba, Go*; Watanabe, Kenichi*; Endo, Tomohiro*; Van Rooijen, W. G.*; Hashimoto, Kengo*; Sakon, Atsushi*; et al.
Journal of Nuclear Science and Technology, 56(8), p.684 - 689, 2019/08
Times Cited Count:12 Percentile:79.53(Nuclear Science & Technology)This study demonstrates, for the first time, the principle of nuclear transmutation of minor actinide (MA) by the accelerator-driven system (ADS) through the injection of high-energy neutrons into the subcritical core at the Kyoto University Critical Assembly. The main objective of the experiments is to confirm fission reactions of neptunium-237 (Np) and americium-241 (Am), and capture reactions of Np. Subcritical irradiation of Np and Am foils is conducted in a hard spectrum core with the use of the back-to-back fission chamber that obtains simultaneously two signals from specially installed test (Np or Am) and reference (uranium-235) foils. The first nuclear transmutation of Np and Am by ADS soundly implemented by combining the subcritical core and the 100 MeV proton accelerator, and the use of a lead-bismuth target, is conclusively demonstrated through the experimental results of fission and capture reaction events.
Hioki, Tomosato*; Hashimoto, Yusuke*; Johansen, T. H.*; Saito, Eiji
Physical Review Applied (Internet), 11(6), p.061007_1 - 061007_5, 2019/06
Times Cited Count:7 Percentile:36.99(Physics, Applied)Minato, Futoshi; Tsukada, Kazuaki; Sato, Nozomi*; Watanabe, Satoshi*; Saeki, Hideya*; Kawabata, Masako*; Hashimoto, Shintaro; Nagai, Yasuki*
Journal of the Physical Society of Japan, 86(11), p.114803_1 - 114803_6, 2017/11
Times Cited Count:10 Percentile:56.7(Physics, Multidisciplinary)We have measured the yield of Mo, the mother nuclide of Tc used in nuclear diagnostic procedure. Mo was produced by Mo(,)Mo using neutrons with thermal energy up to about 40 MeV, provided by C(,). The Mo yield agrees with an estimated yield with the use of the latest data of C(,) and the evaluated cross section given in the JENDL. Based on this, a new calculation was carried out to produce Mo to seek for a good economical condition. Various conditions such as the MoO sample mass, the distance between the carbon target and the sample, the radius of the deuteron beam, and the neutron irradiation time were considered. The calculated Mo yield indicates that about 30% of the Mo demand in Japan can be fulfilled with a single accelerator. The elusion of Tc from the Mo twice per day would meet about 50% of the Mo demand.
Yamaguchi, Daisuke; Yuasa, Takeshi*; Sone, Takuo*; Tominaga, Tetsuo*; Noda, Yohei*; Koizumi, Satoshi*; Hashimoto, Takeji*
Macromolecules, 50(19), p.7739 - 7759, 2017/10
Times Cited Count:14 Percentile:48.33(Polymer Science)We elucidated the spatial distribution of filler particles in cross-linked poly(styrene--butadiene) rubbers (SBR) developed under a typical fillers/rubbers compounding process as one of dissipative structures formed under a stress field imposed on the given system. The dispersion state of the fillers in SBR was clarified on the basis of hierarchical structures consisting of five structure levels. More specifically, it has the following characteristics depending on the specific interactions: Small, compact clusters build up compact mass-fractal structures, while large, loose clusters build up open mass-fractal structures.
Hayakawa, Takehito; Miyamoto, Shuji*; Hajima, Ryoichi; Shizuma, Toshiyuki; Amano, So*; Hashimoto, Satoshi*; Misawa, Tsuyoshi*
Journal of Nuclear Science and Technology, 53(12), p.2064 - 2071, 2016/12
Times Cited Count:6 Percentile:43.12(Nuclear Science & Technology)We have proposed a new selective isotope transmutation method using photonuclear reactions with quasi-monochromatic -ray beams. This method is based on the fact that the particle threshold of a long-lived fission product (LLFP) such as Zr, Pd, or Se is lower than those of stable isotopes of the same chemical element. Therefore, this method has an excellent advantage that LLFPs cannot, in principle, be produced newly even if the target materials include stable isotopes in addition to a LLFP. Laser Compton scattering -ray sources and neutron capture -rays in nuclear reactors are candidates for this method.
Iwamoto, Yosuke; Sato, Tatsuhiko; Niita, Koji*; Hashimoto, Shintaro; Ogawa, Tatsuhiko; Furuta, Takuya; Abe, Shinichiro; Kai, Takeshi; Matsuda, Norihiro; Iwase, Hiroshi*; et al.
JAEA-Conf 2016-004, p.63 - 69, 2016/09
A general purpose Monte Carlo Particle and Heavy Ion Transport code System, PHITS, is being developed through the collaboration of several institutes. PHITS can deal with the transport of nearly all particles, including neutrons, protons, heavy ions, photons, and electrons, over wide energy ranges using various nuclear reaction models and data libraries. PHITS users apply the code to various research and development fields such as nuclear technology, accelerator design, medical physics, and cosmic-ray research. This presentation briefly summarizes the physics models implemented in PHITS, and introduces some new models such as muon-induced nuclear reaction model and a de-excitation model EBITEM. We will also present the radiation damage cross sections for materials, PKA spectra and kerma factors calculated by PHITS under the IAEA-CRP activity titled "Primary radiation damage cross section."
Tonai, Satoshi*; Ito, Shun*; Hashimoto, Yoshitaka*; Tamura, Hajimu; Tomioka, Naotaka*
Journal of Structural Geology, 89, p.19 - 29, 2016/08
Times Cited Count:16 Percentile:48.38(Geosciences, Multidisciplinary)We used the K-Ar ages of clay-sized mineral grains to investigate the timing of activity on the fossil seismogenic Minami-Awa Fault. The K-Ar ages from matrix shale of the mlange range from 85 to 48 Ma and decrease with decreasing amount of detrital mica. In contrast, the K-Ar ages of an ultracataclasite within the fault core are significantly younger, ranging from 29 to 23 Ma, and are unrelated to grain size. This indicates that Ar diffused completely from the ultracataclasite between 29 and 23 Ma. The diffusion of Ar in the ultracataclasite was probably caused by frictional heating or high-temperature fluid migration that occurred when the fault was reactivated. The results indicate that seismogenic faults that separate tectonic mlange from coherent strata in accretionary complex may slip, not only during accretion, but also long after accretion.
Ohshima, Hiroyuki; Uwaba, Tomoyuki; Hashimoto, Akihiko*; Imai, Yasutomo*; Ito, Masahiro*
AIP Conference Proceedings 1702, p.040011_1 - 040011_4, 2015/12
A numerical simulation system, which consists of a deformation analysis program and three kinds of thermal-hydraulics analysis programs, is being developed in Japan Atomic Energy Agency in order to offer methodologies to clarify thermal-hydraulic phenomena in fuel assemblies of sodium-cooled fast reactors under various operating conditions including fuel deformation. This paper gives a summary of numerical methods of component programs of the system and their validation studies.
Sato, Tatsuhiko; Niita, Koji*; Matsuda, Norihiro; Hashimoto, Shintaro; Iwamoto, Yosuke; Furuta, Takuya; Noda, Shusaku; Ogawa, Tatsuhiko; Iwase, Hiroshi*; Nakashima, Hiroshi; et al.
Annals of Nuclear Energy, 82, p.110 - 115, 2015/08
Times Cited Count:35 Percentile:94.59(Nuclear Science & Technology)The general purpose Monte Carlo Particle and Heavy Ion Transport code System, PHITS, is being developed through a collaboration of several institutes in Japan and Europe. The Japan Atomic Energy Agency is responsible for managing the entire project. PHITS can deal with the transport of nearly all particles, including neutrons, protons, heavy ions, photons, and electrons, over wide energy ranges using various nuclear reaction models and data libraries. This paper briefly summarizes the physics models implemented in PHITS, and introduces some important functions useful for particular purposes, such as an event generator mode and beam transport functions.
Watanabe, Satoshi; Hashimoto, Kazuyuki; Ishioka, Noriko
JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 102, 2015/03
Iwamoto, Yosuke; Sato, Tatsuhiko; Niita, Koji*; Matsuda, Norihiro; Hashimoto, Shintaro; Furuta, Takuya; Noda, Shusaku; Ogawa, Tatsuhiko; Iwase, Hiroshi*; Nakashima, Hiroshi; et al.
JAEA-Conf 2014-002, p.69 - 74, 2015/02
A general purpose Monte Carlo Particle and Heavy Ion Transport code System, PHITS, is being developed through the collaboration of several institutes in Japan and Europe. PHITS can deal with the transport of nearly all particles, including neutrons, protons, heavy ions, photons, and electrons, over wide energy ranges using various nuclear reaction models and data libraries. All components of PHITS such as its source, executable and data-library files are assembled in one package and then distributed to many countries. More than 1,000 researchers apply the code to various research and development fields such as nuclear technology, accelerator design, medical physics, and cosmic-ray research. This presentation briefly summarizes the physics models implemented in PHITS, and introduces some important functions for specific applications, such as an event generator mode and a radiation damage calculation function.
Watanabe, Satoshi; Hashimoto, Kazuyuki; Ishioka, Noriko
Journal of Radioanalytical and Nuclear Chemistry, 303(2), p.1519 - 1521, 2015/02
Times Cited Count:10 Percentile:64.26(Chemistry, Analytical)As basic studies of bifunctional chelating agent for Lu-labeled antibodies, Lu complexation of DOTA and DTPA was investigated by the addition of competing metals, Ca(II), Fe(II) and Zn(II). From comparison of competing metals, the inhibition by competing metals on the Lu complexation was in the order of Ca(II) Fe(II) Zn(II) and Ca(II) Zn(II) Fe(II) as DOTA and DTPA, respectively. For comparison between DOTA and DTPA, the susceptibility to the inhibition on Lu complexation by all the three competing metals was DTPA DOTA. Therefore, it was found that DTPA is advantageous for Lu complexation compared with DOTA in the presence of Ca(II), Fe(II) and Zn(II), and that the elimination of Fe from Lu solution is especially effective because the Lu complexation of DTPA is highly inhibited by Fe(II).
Noda, Shusaku; Hashimoto, Shintaro; Sato, Tatsuhiko; Fukahori, Tokio; Chiba, Satoshi*; Niita, Koji*
Journal of Nuclear Science and Technology, 52(1), p.57 - 62, 2015/01
Times Cited Count:14 Percentile:72.94(Nuclear Science & Technology)The author improved the photonuclear reaction model in the PHITS code for incident photon energy below 140 MeV. There are three major improvements: (1) JENDL Photonuclear Data File (JENDL/PD-2004) is adopted to determine the total reaction cross section, (2) the evaporation model for the giant resonance of some light nuclei is modified considering the isospin selection rule, and (3) the quasideuteron disintegration process is implemented in the JAERI Quantum Molecular Dynamics model. The improved PHITS code can contribute to various practical applications such as neutron dose estimation in X-ray therapy.
Watanabe, Satoshi; Hashimoto, Kazuyuki; Watanabe, Shigeki; Iida, Yasuhiko*; Hanaoka, Hirofumi*; Endo, Keigo*; Ishioka, Noriko
Journal of Radioanalytical and Nuclear Chemistry, 303(1), p.935 - 940, 2015/01
Times Cited Count:11 Percentile:67.09(Chemistry, Analytical)