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Nasu, Mitsunori*; Yanai, Hiroshi*; Hirayama, Naoki*; Adachi, Hironori*; Kakizawa, Yu*; Shirase, Yuto*; Nishiyama, Hiromichi*; Kawamoto, Teppei*; Inukai, Junji*; Shinohara, Takenao; et al.
Journal of Power Sources, 530, p.231251_1 - 231251_11, 2022/05
Times Cited Count:18 Percentile:90.63(Chemistry, Physical)Takahashi, Tomoyuki*; Fukaya, Yukiko*; Iimoto, Takeshi*; Uni, Yasuo*; Kato, Tomoko; Sun, S.*; Takeda, Seiji; Nakai, Kunihiro*; Nakabayashi, Ryo*; Uchida, Shigeo*; et al.
Hoken Butsuri (Internet), 56(4), p.288 - 305, 2021/12
We report the results of activities related to the Task Group of Parameters Used in Biospheric Dose Assessment Models for Radioactive Waste Disposal at the Japan Health Physics Society.
Hikima, Kazuhiro*; Hinuma, Yoyo*; Shimizu, Keisuke*; Suzuki, Kota*; Taminato, So*; Hirayama, Masaaki*; Masuda, Takuya*; Tamura, Kazuhisa; Kanno, Ryoji*
ACS Applied Materials & Interfaces, 13(6), p.7650 - 7663, 2021/02
Times Cited Count:12 Percentile:65.55(Nanoscience & Nanotechnology)We evaluated the structural change of the cathode material LiMnO that was deposited as an epitaxial film with an (001) orientation in an all-solid-state battery. In case of the electrode with LiPO coating. Experiments revealed a structural change to a high-capacity (activated) phase that proceeded gradually and continuously with cycling. The activated phase barely showed any capacity fading. We propose a mechanism of structural change with cycling: charging to a high voltage at a sufficiently low Li concentration typically induces irreversible transition to a phase detrimental to cycling that could, but not necessarily, be accompanied by the dissolution of Mn and/or the release of O into the electrolyte, while a gradual irreversible transition to an activated phase happens at a similar Li concentration under a lower voltage.
Okamura, Hiroyuki; Hirayama, Naoki*
Analytical Sciences, 37(1), p.119 - 130, 2021/01
Times Cited Count:32 Percentile:76.52(Chemistry, Analytical)This review summarizes recent progress in solvent extraction of rare earth elements (REEs) using an ionic liquid (IL) as the extraction solvent. These IL extraction systems are advantageous owing to the affinity of ILs for both charged and neutral hydrophobic species, in contrast to conventional organic solvent extraction systems. Herein, REE extraction studies using ILs are detailed and classified based on the type of extraction system. In IL extraction systems, the extracted complexes are often different from those in organic solvent systems, and the REE extraction and separation efficiencies are often significantly enhanced. Synergistic IL extraction is an effective approach to improving the extractability and separability of REEs. The development of novel task-specific ionic liquids (TSILs) suitable for IL extraction systems is also effective for REE separation.
Okamura, Hiroyuki; Mizuno, Masayoshi*; Hirayama, Naoki*; Shimojo, Kojiro; Naganawa, Hirochika; Imura, Hisanori*
Industrial & Engineering Chemistry Research, 59(1), p.329 - 340, 2020/01
Times Cited Count:15 Percentile:56.16(Engineering, Chemical)The synergistic ionic-liquid extraction and extraction equilibrium of lanthanoid(III) (Ln(III)) ions have been investigated using 2-thenoyltrifluoroacetone (Htta) and trioctylphosphine oxide (TOPO) in the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Cmim][TfN]). The selective synergistic effect for heavier Ln(III) ions was found using a combination of Htta and TOPO in [Cmim][TfN], leading to enhanced separability among Ln(III) ions. The extracted Ln(III) species and the extraction constants in the Htta-TOPO system were determined by three-dimensional extraction equilibrium analysis. The selective synergism for heavier Ln(III) ions in the Htta-TOPO system was ascribed to the formation of hydrophobic, charged adducts, such as Ln(tta)(TOPO) and Ln(tta)(TOPO), in [Cmim][TfN].
Wang, H.*; Otsu, Hideaki*; Chiga, Nobuyuki*; Kawase, Shoichiro*; Takeuchi, Satoshi*; Sumikama, Toshiyuki*; Koyama, Shumpei*; Sakurai, Hiroyoshi*; Watanabe, Yukinobu*; Nakayama, Shinsuke; et al.
Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07
Times Cited Count:8 Percentile:55.27(Physics, Multidisciplinary)Searching for effective pathways for the production of proton- and neutron-rich isotopes through an optimal combination of reaction mechanism and energy is one of the main driving forces behind experimental and theoretical nuclear reaction studies as well as for practical applications in nuclear transmutation of radioactive waste. We report on a study on incomplete fusion induced by deuteron, which contains one proton and one neutron with a weak binding energy and is easily broken up. This reaction study was achieved by measuring directly the cross sections for both proton and deuteron for Pd at 50 MeV/u via inverse kinematics technique. The results provide direct experimental evidence for the onset of a cross-section enhancement at high energy, indicating the potential of incomplete fusion induced by loosely-bound nuclei for creating proton-rich isotopes and nuclear transmutation of radioactive waste.
Ito, Yuta*; Schury, P.*; Wada, Michiharu*; Arai, Fumiya*; Haba, Hiromitsu*; Hirayama, Yoshikazu*; Ishizawa, Satoshi*; Kaji, Daiya*; Kimura, Sota*; Koura, Hiroyuki; et al.
Physical Review Letters, 120(15), p.152501_1 - 152501_6, 2018/04
Times Cited Count:60 Percentile:93.38(Physics, Multidisciplinary)Masses of Es, Fm and the transfermium nuclei Md, and No, produced by hot- and cold-fusion reactions, in the vicinity of the deformed neutron shell closure, have been directly measured using a multi-reflection time-of-flight mass spectrograph. The masses of Es and Md were measured for the first time. Using the masses of Md as anchor points for decay chains, the masses of heavier nuclei, up to Bh and Mt, were determined. These new masses were compared with theoretical global mass models and demonstrated to be in good agreement with macroscopic-microscopic models in this region. The empirical shell gap parameter derived from three isotopic masses was updated with the new masses and corroborate the existence of the deformed neutron shell closure for Md and Lr.
Schury, P.*; Wada, Michiharu*; Ito, Yuta*; Kaji, Daiya*; Haba, Hiromitsu*; Hirayama, Yoshikazu*; Kimura, Sota*; Koura, Hiroyuki; MacCormick, M.*; Miyatake, Hiroari*; et al.
Nuclear Instruments and Methods in Physics Research B, 407, p.160 - 165, 2017/06
Times Cited Count:14 Percentile:79.44(Instruments & Instrumentation)Various isotopes of Ac, Ra, Fr, and Rn were produced by fusion-evaporation reactions using a Ca beam. The energetic ions were stopped in and extracted from a helium gas cell. The extracted ions were identified using a multi-reflection time-of-fight mass spectrograph. In all cases, it was observed that the predominant charge state for the extracted ions, including the alkali Fr, was 2+.
Das, S. K.*; Fukuda, Tomokazu*; Mizoi, Yutaka*; Ishiyama, Hironobu*; Miyatake, Hiroari*; Watanabe, Yutaka*; Hirayama, Yoshikazu*; Jeong, S. C.*; Ikezoe, Hiroshi*; Matsuda, Makoto; et al.
Physical Review C, 95(5), p.055805_1 - 055805_4, 2017/05
Times Cited Count:3 Percentile:26.98(Physics, Nuclear)Abe, Machiko*; Iba, Hideki*; Suzuki, Kota*; Minamishima, Hiroaki*; Hirayama, Masaaki*; Tamura, Kazuhisa; Mizuki, Junichiro*; Saito, Tomohiro*; Ikuhara, Yuichi*; Kanno, Ryoji*
Journal of Power Sources, 345, p.108 - 119, 2017/03
Times Cited Count:11 Percentile:38.14(Chemistry, Physical)The surface structure of the Li(Ni, Co, Mn)O electrode was studied during charge/discharge process using electrochemical methods and X-ray/Neutron scattering techniques. It was found that during charge/discharge process the coverage of spinel structure increased. The spinel structure has low electrochemical activity and is not involved in Li insertion/extraction. After the surface modification, it was found that the coverage of the spinel structure did not increase. Further, it was also found out that the Li concentration at the electrode/electrolyte interface increased.
Kunieda, Satoshi; Iwamoto, Osamu; Iwamoto, Nobuyuki; Minato, Futoshi; Okamoto, Tsutomu; Sato, Tatsuhiko; Nakashima, Hiroshi; Iwamoto, Yosuke; Iwamoto, Hiroki; Kitatani, Fumito; et al.
JAEA-Conf 2016-004, p.41 - 46, 2016/09
Neutron- and proton-induced cross-section data are required in a wide energy range beyond 20 MeV, for the design of accelerator applications. New evaluations are performed with recent knowledge in the optical and pre-equilibrium model calculations. We also evaluated cross-sections for p+Li and p+Be which have been highly requested from a medical field. The present high-energy nuclear data library, JENDL-4.0/HE, includes evaluated cross-sections for incident neutrons and protons up to 200 MeV (for about 130 nuclei). We overview substantial features of the library, i.e., (1) systematic evaluation with CCONE code, (2) challenges for evaluations of light nuclei and (3) inheritance of JENDL-4.0 and JENDL/HE-2007. In this talk, we also focus on the results of benchmark calculation for neutronics to show performance of the present library.
Sato, Takeshi; Muto, Shigeo; Okuno, Hiroshi; Katagiri, Hiromi; Akiyama, Kiyomitsu; Okamoto, Akiko; Koie, Masahiro; Ikeda, Takeshi; Nemotochi, Toshimasa; Saito, Toru; et al.
JAEA-Review 2013-046, 65 Pages, 2014/02
When a nuclear emergency occurs in Japan, the Japan Atomic Energy Agency (JAEA) has the responsibility of providing technical support to the National government, local governments, police, fire stations and nuclear operators etc., because the JAEA has been designated as the Designated Public Institution under the Basic Act on Disaster Control Measures and the Act on Response to Armed Attack Situations, etc.. The Nuclear Emergency Assistance and Training Center (NEAT) of JAEA provides a comprehensive range of technical support activities to an Off-Site Center in case of a nuclear emergency. Specifically, NEAT gives technical advice and information, dispatches specialists as required, and supplies the National Government and local governments with emergency equipments and materials. NEAT provides various exercise and training courses concerning nuclear disaster prevention to those personnel taking an active part in emergency response organizations at normal times. The tasks of NEAT, with its past experiences as a designated public institution including the responses to TEPCO's Fukushima Accident, have been shifted to technical supports to the national government for strengthening its abilities to emergency responses; the NEAT therefore focused on maintenance and operation of its functions, and strengthening its response abilities in cooperation with the national government. This annual report summarized these activities of JAEA/NEAT in the fiscal year 2012.
Sonoda, Tetsu*; Wada, Michiharu*; Tomita, Hideki*; Sakamoto, Chika*; Takatsuka, Takaaki*; Furukawa, Takeshi*; Iimura, Hideki; Ito, Yuta*; Kubo, Toshiyuki*; Matsuo, Yukari*; et al.
Nuclear Instruments and Methods in Physics Research B, 295, p.1 - 10, 2013/01
Times Cited Count:21 Percentile:83.46(Instruments & Instrumentation)no abstracts in English
Okamura, Hiroyuki; Ikeda, Atsushi*; Saito, Takumi*; Aoyagi, Noboru; Naganawa, Hirochika; Hirayama, Naoki*; Umetani, Shigeo*; Imura, Hisanori*; Shimojo, Kojiro
Analytical Chemistry, 84(21), p.9332 - 9339, 2012/11
Times Cited Count:23 Percentile:62.19(Chemistry, Analytical)Kasugai, Yoshimi; Matsuda, Norihiro; Sakamoto, Yukio; Nakashima, Hiroshi; Yashima, Hiroshi*; Matsumura, Hiroshi*; Iwase, Hiroshi*; Hirayama, Hideo*; Mokhov, N.*; Leveling, A.*; et al.
Reactor Dosimetry; 14th International Symposium (ASTM STP 1550), p.675 - 689, 2012/08
Under the collaborative study project of JASMIN, shielding experiments has been carried out using the anti-proton target station (Pbar) of Fermilab. In the experiment, the multi-foil activation technique was utilized, and the neutron spectra in high-energy region between 1 and 100 MeV were deduced by using the "fitting method", which is newly developed. In this method, we made an assumption that neutron energy spectra could be expressed with a simple function. The validity of the fitting method was confirmed by comparison with the results of the unfolding method and the theoretical calculations. Finally, it was found that there are simple correlations between reaction rates and the adjusting parameters in the fitting function. The correlations are useful for estimating the adjusting parameters easily, and a neutron spectrum in the high-energy region can be deduced from a set of reaction-rate data without the complicated calculations of unfolding.
Ishiyama, Hironobu*; Yamaguchi, Kanako*; Mizoi, Yutaka*; Watanabe, Yutaka*; Das, S. K.*; Hashimoto, Takashi*; Miyatake, Hiroari*; Hirayama, Yoshikazu*; Imai, Nobuaki*; Oyaizu, Mitsuhiro*; et al.
Journal of Instrumentation (Internet), 7(3), p.C03036_1 - C03036_14, 2012/03
Times Cited Count:8 Percentile:37.43(Instruments & Instrumentation)We developed an active-target type gas counter operating with low He/CO (10%) detector gas for application in studying low-energy nuclear reactions using radioactive beams. A 400-m-thick gas electron multiplier (THGEM) was used as the proportional counter for high injection rate capability. We examined the gas gain stability and the influence of ion feedback on particle tracks at high beam injection rates of up to 10 particles per second (pps) using a low-energy C beam. From the result of this examination, we found that the THGEM was found to be applicable for our active target at high injection rates of up to 10 pps.
Okamura, Hiroyuki; Sakae, Hiroki*; Kidani, Keiji*; Hirayama, Naoki*; Aoyagi, Noboru; Saito, Takumi*; Shimojo, Kojiro; Naganawa, Hirochika; Imura, Hisanori*
Polyhedron, 31(1), p.748 - 753, 2012/01
Times Cited Count:29 Percentile:88(Chemistry, Inorganic & Nuclear)Matsuda, Norihiro; Kasugai, Yoshimi; Sakamoto, Yukio; Nakashima, Hiroshi; Matsumura, Hiroshi*; Iwase, Hiroshi*; Kinoshita, Norikazu*; Hirayama, Hideo*; Yashima, Hiroshi*; Mokhov, N.*; et al.
Journal of the Korean Physical Society, 59(2), p.2055 - 2058, 2011/08
Times Cited Count:0 Percentile:0(Physics, Multidisciplinary)It is important to obtain neutron spectra and its intensity on shielding experiment. Deduction of high-energy neutron spectra were done using fitting and unfolding methods based on the shielding data obtained at the anti-proton (pbar) target station in Fermilab. The neutron spectra for fitting method is useful to be easily obtained and the values gave reasonable results compared with nuclear data. Therefore, that for unfolding methods included inconsistency. Furthermore, the deduced neutron spectra were verified through the calculation analyses by PHITS code.
Shigyo, Nobuhiro*; Hidaka, Kosuke*; Hirabayashi, Keiichi*; Nakamura, Yasuhiro*; Moriguchi, Daisuke*; Kumabe, Masahiro*; Hirano, Hidetaka*; Hirayama, Shusuke*; Naito, Yuki*; Motooka, Chikahide*; et al.
Journal of the Korean Physical Society, 59(2), p.1725 - 1728, 2011/08
Yashima, Hiroshi*; Kasugai, Yoshimi; Matsuda, Norihiro; Matsumura, Hiroshi*; Iwase, Hiroshi*; Kinoshita, Norikazu*; Mokhov, N.*; Leveling, A.*; Boehnlein, D.*; Vaziri, K.*; et al.
Progress in Nuclear Science and Technology (Internet), 1, p.48 - 51, 2011/02
The shielding experiment was performed at the anti-proton production target station in Fermi National Accelerator Laboratory. Aluminum, Bismath, Niobium, Copper and Indium samples were placed behind the shields. After irradiation, induced activities of samples were measured by using HPGe detector. The spatial distribution of reaction rate of samples which were placed behind the iron and concrete shields were obtained. The measured data shows that the reaction rates on the outer surfaces of the iron and concrete shields increases toward the downstream of the target. The obtained reaction rates were also fitted to Moyer's formula, and the attenuation lengths for iron and concrete shields were obtained.