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Amekura, Hiroshi*; Chettah, A.*; Narumi, Kazumasa*; Chiba, Atsuya*; Hirano, Yoshimi*; Yamada, Keisuke*; Yamamoto, Shunya*; Leino, A. A.*; Djurabekova, F.*; Nordlund, K.*; et al.
Nature Communications (Internet), 15, p.1786_1 - 1786_10, 2024/02
Injecting high-energy heavy ions in the electronic stopping regime into solids can create cylindrical damage zones called latent ion tracks. Although these tracks form in many materials, none have ever been observed in diamond, even when irradiated with high-energy GeV uranium ions. Here we report the first observation of ion track formation in diamond irradiated with 2-9 MeV C fullerene ions. Depending on the ion energy, the mean track length (diameter) changed from 17 (3.2) nm to 52 (7.1) nm. High resolution scanning transmission electron microscopy (HR-STEM) indicated the amorphization in the tracks, in which -bonding signal from graphite was detected by the electron energy loss spectroscopy (EELS).
Shimokita, Keisuke*; Yamamoto, Katsuhiro*; Miyata, Noboru*; Nakanishi, Yohei*; Shibata, Motoki*; Takenaka, Mikihito*; Yamada, Norifumi*; Seto, Hideki*; Aoki, Hiroyuki; Miyazaki, Tsukasa*
Soft Matter, 19(11), p.2082 - 2089, 2023/03
Times Cited Count:0 Percentile:0(Chemistry, Physical)Shimokita, Keisuke*; Yamamoto, Katsuhiro*; Miyata, Noboru*; Arima-Osonoi, Hiroshi*; Nakanishi, Yohei*; Takenaka, Mikihito*; Shibata, Motoki*; Yamada, Norifumi*; Seto, Hideki*; Aoki, Hiroyuki; et al.
Langmuir, 38(41), p.12457 - 12465, 2022/10
Times Cited Count:0 Percentile:0(Chemistry, Multidisciplinary)Kobayashi, Daisuke; Yamamoto, Masahiko; Nishida, Naoki; Miyoshi, Ryuta; Nemoto, Ryo*; Hayashi, Hiroyuki*; Kato, Keisuke; Nishino, Saki; Kuno, Takehiko; Kitao, Takahiko; et al.
Nihon Hozen Gakkai Dai-18-Kai Gakujutsu Koenkai Yoshishu, p.237 - 240, 2022/07
All gloves attached to glove-box in Tokai Reprocessing Plant have a fixed expiration date and have to be replaced every 4-year. However, degrees of glove deterioration are different depending on its usage environment (frequency, chemicals, radiation, etc.), because of rubber products. Therefore, physical properties such as tensile strength, elongation, hardness of gloves are measured, and the life-time of gloves are estimated. As a result, gloves without any defects in its appearance have enough physical property for acceptance criteria of new glove. The extrapolated physical property of glove is sufficiently larger than the reported values of damaged glove. No deterioration in physical properties of gloves, that are periodically replaced without any defects in its appearance, is observed and the usable life-time of the glove is estimated to be 8 years.
Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.
Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07
This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.
Tanaka, Hirohisa*; Masaki, Sayaka*; Aotani, Takuro*; Inagawa, Kohei*; Iwata, Sogo*; Aida, Tatsuya*; Yamamoto, Tadasuke*; Kita, Tomoaki*; Ono, Hitomi*; Takenaka, Keisuke*; et al.
SAE Technical Paper 2022-01-0534 (Internet), 10 Pages, 2022/03
Yamamoto, Seiichi*; Nagao, Yuto*; Kurita, Keisuke; Yamaguchi, Mitsutaka*; Kawachi, Naoki*
Journal of Instrumentation (Internet), 16(1), p.P01007_1 - P01007_9, 2021/01
Times Cited Count:0 Percentile:0(Instruments & Instrumentation)Luminescence of water during irradiation with particles having energies below the Cerenkov-light threshold was recently found for various types of radiations. However, the relation between the intensities of Cerenkov light and of the luminescence of water at the beam energy below the Cherenkov threshold is not well known. To clarify this point, we measured the produced light irradiating a water sample with electron beams having maximum energies above and below the Cerenkov-light threshold.
Amekura, Hiroshi*; Toulemonde, M.*; Narumi, Kazumasa*; Li, R.*; Chiba, Atsuya*; Hirano, Yoshimi*; Yamada, Keisuke*; Yamamoto, Shunya*; Ishikawa, Norito; Okubo, Nariaki; et al.
Scientific Reports (Internet), 11(1), p.185_1 - 185_11, 2021/01
Times Cited Count:12 Percentile:75.03(Multidisciplinary Sciences)We report the track formation of 10 nm in diameter in silicon irradiated with 6 MeV C, i.e., much lower energy than the previously reported energy threshold.
Miyazaki, Tsukasa*; Shimokita, Keisuke*; Yamamoto, Katsuhiro*; Aoki, Hiroyuki; Yamada, Norifumi*; Miyata, Noboru*
Langmuir, 36(49), p.15181 - 15188, 2020/12
Times Cited Count:6 Percentile:31.74(Chemistry, Multidisciplinary)Yoshimatsu, Kohei*; Ishimaru, Junya*; Watarai, Keisuke*; Yamamoto, Kohei*; Hirata, Yasuyuki*; Wadachi, Hiroki*; Takeda, Yukiharu; Horiba, Koji*; Kumigashira, Hiroshi*; Sakata, Osami*; et al.
Physical Review B, 99(23), p.235129_1 - 235129_8, 2019/06
Times Cited Count:10 Percentile:49.82(Materials Science, Multidisciplinary)Fugane, Keisuke*; Mori, Toshiyuki*; Yan, P.*; Masuda, Takuya*; Yamamoto, Shunya; Ye, F.*; Yoshikawa, Hideki*; Auchterlonie, G.*; Drennan, J.*
ACS Applied Materials & Interfaces, 7(4), p.2698 - 2707, 2015/02
Times Cited Count:30 Percentile:67.05(Nanoscience & Nanotechnology)no abstracts in English
Yamamoto, Kento; Okumura, Keisuke; Kojima, Kensuke; Okamoto, Tsutomu
Nuclear Back-end and Transmutation Technology for Waste Disposal, p.233 - 249, 2015/00
To improve the prediction accuracy of concentrations of activation products (APs) in the field of nuclear back-end, it is important to investigate the elements and the nuclear reactions leading to generation of APs. To clarify quantitatively the source elements and the nuclear reactions dominating generation of APs, sensitivity analyses of initial compositions and cross sections were conducted using ORIGEN2.2 code and ORLIBJ40, which is a set of the 1-group cross section libraries based on JENDL-4.0. Activations of cladding tubes, end-plugs and spacers of fuel assemblies and channel boxes in BWR, whose materials are zirconium alloy, stainless steel, and nickel-chromium-based alloy, were analyzed. The results clarified quantitatively the source elements and the nuclear reactions dominating generation of APs. It was remarkable that the dominant generation pathways were clarified even for the nuclides generated through complicated pathways. In conclusion, the results of sensitivity analyses could be utilized to select the objective of elements for measurements of impurities in the materials and of nuclear data for improvement of accuracy.
Tashiro, Koji*; Hanesaka, Makoto*; Yamamoto, Hiroko*; Wasanasuk, K.*; Jayaratri, P.*; Yoshizawa, Yoshinori*; Tanaka, Ichiro*; Niimura, Nobuo*; Kusaka, Katsuhiro*; Hosoya, Takaaki*; et al.
Kobunshi Rombunshu, 71(11), p.508 - 526, 2014/11
Times Cited Count:6 Percentile:22.37(Polymer Science)The crystal structure analysis of various polymer substances has been reviewed on the basis of wide-angle high-energy X-ray and neutron diffraction data. The progress in structural analytical techniques of polymer crystals have been reviewed at first. The structural models proposed so far were reinvestigated and new models have been proposed for various kinds of polymer crystals including polyethylene, poly(vinyl alcohol), poly(lactic acid) and its stereocomplex etc. The hydrogen atomic positions were also clarified by the quantitative analysis of wide-angle neutron diffraction data, from which the physical properties of polymer crystals have been evaluated theoretically. The bonded electron density distribution has been estimated for a polydiacetylene single crystal on the basis of the so-called X-N method or by the combination of structural information derived from X-ray and neutron diffraction data analysis. Some comments have been added about future developments in the field of structure-property relationship determination.
Takahashi, Yukio*; Kadono, Toshiharu*; Yamamoto, Shimpei*; Singh, V. R.*; Verma, V.*; Ishigami, Keisuke*; Shibata, Goro*; Harano, Takayuki*; Takeda, Yukiharu; Okane, Tetsuo; et al.
Physical Review B, 90(2), p.024423_1 - 024423_5, 2014/07
Times Cited Count:11 Percentile:44.58(Materials Science, Multidisciplinary)Yamamoto, Kento; Okumura, Keisuke
Journal of Nuclear Science and Technology, 51(4), p.568 - 573, 2014/04
Times Cited Count:3 Percentile:23.92(Nuclear Science & Technology)To clarify the generation pathway of U in burned fuels, which is an important nuclide for dose evaluation at various stages in fuel cycle, concentrations of U generated through various pathways were evaluated for UO and MOX fuels at 45 GWd/t using the ORIGEN2.2 code. It was found that the difference of U concentrations in UO and MOX fuel are mainly derived from the difference of the initial compositions of U, U and U and the contribution of plutonium and americium isotopes in MOX fuels is not so large compared with that of uranium isotopes. The results clarified that the capture cross sections of Th, Pa, U and U and (,2) cross sections of Np and U have a large effect on generation of U. The additional investigation showed that not only time after irradiation but also time before irradiation has a strong effect on U concentration.
Yamamoto, Kento; Okumura, Keisuke; Kojima, Kensuke; Okamoto, Tsutomu
JAEA-Research 2013-038, 88 Pages, 2014/02
Accurate information on main generation pathways of activation products is important to improve the accuracy of predicting the concentrations of activation products. Using ORIGEN2 and ORLIBJ40, which is a set of the cross section libraries based on JENDL-4.0, the initial compositions and the cross sections which influence on the concentrations of activation products were clarified by executing the sensitivity analyses on them. Activations of cladding tubes, end-plugs and spacers of fuel assemblies and channel boxes, which were composed of Zircaloy, SUS304, and Inconel-718, were analyzed. The main generation pathways of some significant activation products were summarized from the results of sensitivity analyses.
Fukushi, Keisuke*; Hasegawa, Yusuke*; Maeda, Koshi*; Aoi, Yusuke*; Tamura, Akihiro*; Arai, Shoji*; Yamamoto, Yuhei*; Aosai, Daisuke*; Mizuno, Takashi
Environmental Science & Technology, 47(22), p.12811 - 12818, 2013/11
Times Cited Count:27 Percentile:58.19(Engineering, Environmental)Eu(III) sorption on granite was examined by the combined microscopic and macroscopic approaches. Polished thin sections of the granite were reacted with solutions containing 10 M of Eu(III) and analyzed using EPMA and LA-ICP-MS. The Eu enrichment up to 6 wt.% was observed on most of the biotite grains. The Eu-enriched parts commonly lose K, which is the interlayer cation of biotite, indicating that the sorption mode is cation exchange in the interlayer. Batch Eu(III) sorption experiments on granite and biotite powders were conducted. The macroscopic sorption behavior of biotite was consistent with that of granite. The obtained sorption edges can be reproduced reasonably by the modeling considering single-site cation exchange reactions. Granite is complex mineral assemblages. However, the combined microscopic and macroscopic approaches revealed that elementary reactions by single phase can be representative for the bulk sorption reaction in complex mineral assemblages.
Komatsu, Mitsuru*; Nishigaki, Makoto*; Seno, Shoji*; Hirata, Yoichi*; Takenobu, Kazuyoshi*; Tagishi, Hirotaka*; Kunimaru, Takanori; Maekawa, Keisuke; Yamamoto, Yoichi; Toida, Masaru*; et al.
JAEA-Research 2012-001, 77 Pages, 2012/09
This research focused on methods of estimating the amounts of groundwater recharge, which are normally required as upper boundary conditions in groundwater flow analyses, based on measurements of infiltrating water in the ground, to systematize the methods and establish systems which are stable and measurable on site over a long time. Regarding developing measurement systems, fiber-optic strain measurement methods that enable multiple-point and long-distance measurement were used for measuring three quantities: suction pressure, soil moisture and volumetric water content rate obtained by applying water absorption swelling material, and each measurement was discussed. The results showed that the fiber-optic soil aquameter has two types of practical application: one for measuring suction pressure (Type I), and the other for measuring volumetric water content rate obtained by applying water absorption swelling material (Type III). Furthermore, by using measurement instruments in actual fields, the validity of the two methods for estimating the rainfall infiltration capacities of shallow-layer soils, that is, estimating the capacities either directly by measurements of soil water or from unsaturated hydraulic conductivities, was confirmed.
Yamamoto, Yoichi; Maekawa, Keisuke; Yokota, Hideharu; Yamazaki, Masanori
JAEA-Research 2011-042, 97 Pages, 2012/02
The surface hydrogeological investigation has been carried out in and around the Horonobe Underground Research Laboratory area as a part of Horonobe URL project. Observations of meteorological, river flux, water quality, soil moisture and groundwater level have been continued in order to understand the groundwater recharge rate and groundwater flow in the shallow part, which are required for the setting of boundary and initial condition of the groundwater flow analysis. This report shows the summary of the surface hydrogeological investigation and results of recharge rates of investigation basins from December 2004 to November 2009 are calculated by using the water budget method. Spatial estimation of hydrological quantities for the groundwater recharge rate is demonstrated by the runoff analysis. As a result, average of the groundwater recharge rate of whole basins is estimated to 131mm/yr. Suggestive observations related to hydraulic properties of the geology and faults are obtained from consideration to the groundwater recharge rate for each basin.
Komatsu, Hisanori*; Kojima, Kentaro*; Funato, Yoshiki*; Matsuda, Yasuhiro*; Kijimura, Taiki*; Okuyama, Katsushi*; Yamamoto, Hiroko*; Iwami, Yukiteru*; Ebisu, Shigeyuki*; Nomachi, Masaharu*; et al.
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 85, 2012/01