Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Mitsuyasu, Yusuke*; Oka, Toshitaka; Takahashi, Atsushi*; Kino, Yasushi*; Okutsu, Kenichi*; Sekine, Tsutomu*; Yamashita, Takuma*; Shimizu, Yoshinaka*; Chiba, Mirei*; Suzuki, Toshihiko*; et al.
Radiation Protection Dosimetry, 199(14), p.1620 - 1625, 2023/09
Times Cited Count:0 Percentile:0.01(Environmental Sciences)We have been conducting dose assessments for Japanese macaques captured in Fukushima to reveal radiobiological effects on the low-dose expose animals. To accurately determine the external exposure dose, it is desirable to examine the analysis of the CO radical intensity. We examined ESR spectra of teeth of 10 macaques captured in Fukushima by two spectrum-decomposition algorithms.
Nonaka, Yosuke*; Wakabayashi, Yuki*; Shibata, Goro; Sakamoto, Shoya*; Ikeda, Keisuke*; Chi, Z.*; Wan, Y.*; Suzuki, Masahiro*; Tanaka, Arata*; Tanaka, Masaaki*; et al.
Physical Review Materials (Internet), 7(4), p.044413_1 - 044413_10, 2023/04
Times Cited Count:0 Percentile:0.00(Materials Science, Multidisciplinary)Shibata, Goro; Won, C.*; Kim, J.*; Nonaka, Yosuke*; Ikeda, Keisuke*; Wan, Y.*; Suzuki, Masahiro*; Koide, Tsuneharu*; Tanaka, Arata*; Cheong, S.-W.*; et al.
Photon Factory Activity Report 2022 (Internet), 2 Pages, 2023/00
no abstracts in English
Ishikawa, Ryoya*; Suzuki, Masatoshi*; Kino, Yasushi*; Endo, Satoru*; Nakajima, Hiroo*; Oka, Toshitaka; Takahashi, Atsushi*; Shimizu, Yoshinaka*; Suzuki, Toshihiko*; Shinoda, Hisashi*; et al.
KEK Proceedings 2022-2, p.61 - 66, 2022/11
The balance between oxidative stress and antioxidant activity, which is a defense mechanism against oxidative stress, was investigated in the liver and bladder of wild Japanese macaques captured in Fukushima Prefecture. No significant induction of oxidative stress by exposure to environmental radionuclides after the Fukushima nuclear accident was observed, suggesting that the stress defense mechanism of the organism is activated in some organs.
Mitsuyasu, Yusuke*; Oka, Toshitaka; Takahashi, Atsushi*; Kino, Yasushi*; Okutsu, Kenichi*; Sekine, Tsutomu*; Yamashita, Takuma*; Shimizu, Yoshinaka*; Chiba, Mirei*; Suzuki, Toshihiko*; et al.
KEK Proceedings 2022-2, p.120 - 125, 2022/11
We investigate the effect of sample's anisotropy and measurement condition to obtain the higher reproducibility for the shape of the ESR spectrum and the intensity of CO radical.
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:81.82(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.
Oka, Toshitaka; Takahashi, Atsushi*; Koarai, Kazuma; Kino, Yasushi*; Sekine, Tsutomu*; Shimizu, Yoshinaka*; Chiba, Mirei*; Suzuki, Toshihiko*; Osaka, Ken*; Sasaki, Keiichi*; et al.
Journal of Radiation Research (Internet), 63(4), p.609 - 614, 2022/07
Times Cited Count:1 Percentile:23.19(Biology)Electron spin resonance (ESR) dosimetry is one of the most powerful tools for radiation dose reconstruction. The detection limit of this technique using human teeth is reported to be 56 mGy or 67 mGy; however, the absorbed dose of Fukushima residents after the Fukushima Daiichi Nuclear Power Plant (FNPP) accident was estimated to be lower than this detection limit. Our aim is to assess the absorbed radiation dose of children in Fukushima Prefecture after the accident; therefore, it is important to estimate the detection limit for their teeth. The detection limit for enamel of deciduous teeth of Japanese children separated by the mechanical method is estimated to be 115.0 mGy. The density separation method can effectively separate enamel from third molars of Japanese people. As we have collected thousands of teeth from children in Fukushima, the present technique may be useful to examine their external absorbed dose after the FNPP accident.
Suzuki, Hakuto*; Zhao, G.*; Okamoto, Jun*; Sakamoto, Shoya*; Chen, Z.-Y.*; Nonaka, Yosuke*; Shibata, Goro; Zhao, K.*; Chen, B.*; Wu, W.-B.*; et al.
Journal of the Physical Society of Japan, 91(6), p.064710_1 - 064710_5, 2022/06
Times Cited Count:0 Percentile:0.00(Physics, Multidisciplinary)Gtz, M.*; Yakushev, A.*; Gtz, S.*; Di Nitto, A.*; Dllmann, Ch. E.*; Asai, Masato; Kindler, B.*; Krier, J.*; Lommel, B.*; Nagame, Yuichiro*; et al.
Radiochimica Acta, 110(2), p.75 - 86, 2022/02
Times Cited Count:2 Percentile:29.53(Chemistry, Inorganic & Nuclear)The study of volatile superheavy element carbonyl complexes requires more efficient methods because the yield of transactinide elements decreases with increasing atomic number. This is achieved by using a newly developed double chamber system to separate the recoil chamber and the reaction one, thereby avoiding the decomposition of reactive molecules by the projectile ion beam, which hinders the synthesis of carbonyl complexes. The feasibility of this method was verified by synthesizing 5d metal short-lived isotopes as homologous element isotopes of the light transactinide elements Sg, Bh, Hs, and Mt at the Japan Atomic Energy Agency tandem accelerator and conducting model experiments.
Mitsuyasu, Yusuke*; Oka, Toshitaka; Takahashi, Atsushi*; Koarai, Kazuma; Kino, Yasushi*; Okutsu, Kenichi*; Sekine, Tsutomu*; Yamashita, Takuma*; Shimizu, Yoshinaka*; Chiba, Mirei*; et al.
KEK Proceedings 2021-2, p.91 - 96, 2021/12
We examined whether the ESR dose estimation method could be applied to wild Japanese macaque. In this work, we investigated the enamel preparation protocol and the analytical method of the ESR spectra.
Koarai, Kazuma; Matsueda, Makoto; Aoki, Jo; Yanagisawa, Kayo*; Terashima, Motoki; Fujiwara, Kenso; Kino, Yasushi*; Oka, Toshitaka; Takahashi, Atsushi*; Suzuki, Toshihiko*; et al.
Journal of Analytical Atomic Spectrometry, 36(8), p.1678 - 1682, 2021/08
Times Cited Count:5 Percentile:53.20(Chemistry, Analytical)Rapid analysis of Sr in bone and tooth samples of cattle were achieved by an inductively coupled plasma mass spectrometry (ICP-MS) coupled with mass shift and solid phase extraction techniques. Limit of detection (LOD) in the ICP-MS measurement of 0.1 g samples was lower than that of the radioactivity measurement. Analytical time of the ICP-MS method was reduced from 20 days to 11 hours, compared with the radiometric method. Therefore, the ICP-MS method can be rapid and useful procedure of Sr in small bone and tooth samples derived from terrestrial animals.
Taguchi, Shigeo; Taguchi, Katsuya; Makino, Risa; Yamanaka, Atsushi; Suzuki, Kazuyuki; Takano, Masato; Koshino, Katsuhiko; Ishida, Michihiko; Nakano, Takafumi; Yamaguchi, Toshiya
Nihon Hozen Gakkai Dai-17-Kai Gakujutsu Koenkai Yoshishu, p.499 - 502, 2021/07
In 2018, Tokai Reprocessing Plan (TRP) shifted to the decommissioning stage. In order to proceed with steady decommissioning work, TRP effort to enhance project management function. This paper describes the establishment and role of the Decommissioning Project Management Office, effectiveness of applying the project management tool and its utilization concept, and the method of materialize the equipment dismantling plan.
Sakamoto, Atsushi; Kibe, Satoshi*; Kawanobe, Kazunori*; Fujisaku, Kazuhiko*; Sano, Yuichi; Takeuchi, Masayuki; Suzuki, Hideya*; Tsubata, Yasuhiro; Ban, Yasutoshi; Matsumura, Tatsuro
JAEA-Research 2021-003, 30 Pages, 2021/06
Japan Atomic Energy Agency has been developing a solvent extraction process called SELECT to recover minor actinides (MA) from spent nuclear fuel. In the SELECT process, TDdDGA, HONTA, and ADAAM are used as the extractants for MA + Ln corecovery, MA/Ln separation and Am/Cm separation, respectively. These extractants do not contain phosphorus (P), and consist of carbon (C), hydrogen (H), oxygen (O), and nitrogen (N). In this study, in order to give beneficial information for designing flowsheet, the mass transfer coefficients of Ln between HNO solution and TDdDGA or HONTA / n-dodecane solvent were evaluated by the single drop technique. Prior to the evaluation of mass transfer coefficient, we had optimized the structure of the single drop apparatus to improve accuracy of the measurement. Based on the mass transfer coefficients obtained in HNO / TDdDGA-n-dodecane system, Ln behaviors in the counter-current extraction and back-extraction using mixer-settlers and centrifugal contactors were estimated by simple calculation, and they had a good agreement with our previous experimental results. We also confirmed the mass transfer coefficients of Ln in HNO / HONTA - n-dodecane system are under 10 m/s.
Kobayashi, Masaki*; Anh, L. D.*; Suzuki, Masahiro*; Kaneta-Takada, Shingo*; Takeda, Yukiharu; Fujimori, Shinichi; Shibata, Goro*; Tanaka, Arata*; Tanaka, Masaaki*; Oya, Shinobu*; et al.
Physical Review Applied (Internet), 15(6), p.064019_1 - 064019_10, 2021/06
Times Cited Count:5 Percentile:42.31(Physics, Applied)Takahashi, Atsushi*; Chiba, Mirei*; Tanahara, Akira*; Aida, Jun*; Shimizu, Yoshinaka*; Suzuki, Toshihiko*; Murakami, Shinobu*; Koarai, Kazuma; Ono, Takumi*; Oka, Toshitaka; et al.
Scientific Reports (Internet), 11(1), p.10355_1 - 10355_11, 2021/05
Times Cited Count:6 Percentile:38.85(Multidisciplinary Sciences)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:44 Percentile:96.99(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.
Go, Shintaro*; Ideguchi, Eiji*; Yokoyama, Rin*; Aoi, Nori*; Azaiez, F.*; Furutaka, Kazuyoshi; Hatsukawa, Yuichi; Kimura, Atsushi; Kisamori, Keiichi*; Kobayashi, Motoki*; et al.
Physical Review C, 103(3), p.034327_1 - 034327_8, 2021/03
Times Cited Count:4 Percentile:54.40(Physics, Nuclear)Komatsu, Kazuki*; Iwasaki, Tsugumi*; Murata, Kosuke*; Yamashiro, Hideaki*; Goh, V. S. T.*; Nakayama, Ryo*; Fujishima, Yohei*; Ono, Takumi*; Kino, Yasushi*; Shimizu, Yoshinaka*; et al.
Reproduction in Domestic Animals, 56(3), p.484 - 497, 2021/03
Times Cited Count:9 Percentile:85.28(Agriculture, Dairy & Animal Science)We have established an archive system of livestock and wild animals from the surrounding ex-evacuation zone. Wildlife within the alert zone have been exposed to low-dose-rate (LDR) radiation for a long and continuous time. In this study, we analysed the morphological characteristics of the testes and in vitro fertilization (IVF) capacity of cryopreserved sperm of raccoons from the ex-evacuation zone of the FDNPP accident. This study revealed that the chronic and LDR radiation exposure associated with the FDNPP accident had no adverse effect on the reproductive characteristics and functions of male raccoons.
Shimojo, Kojiro; Suzuki, Hideya; Yokoyama, Keiichi; Yaita, Tsuyoshi; Ikeda, Atsushi
Analytical Sciences, 36(12), p.1435 - 1437, 2020/12
Times Cited Count:14 Percentile:65.87(Chemistry, Analytical)Liquid-liquid extraction for the removal of pertechnetate (TcO) and perrhenate (ReO) is reported using tripodal extractant -hexa--octylnitrilotriacetamide (HONTA) composed of three amide groups and a tertiary amine. The extraction behavior was compared with those using alkyldiamideamines (ADAAM(Oct) and ADAAM(EH)), and the commercial amine-type extractant, trioctylamine (TOA). HONTA quantitatively extracted TcO and ReO in the pH range from 1.0 to 2.5 by co-extraction of protons. Extraction performance of extractants was improved in the order of HONTA ADAAM(Oct) ADAAM(EH) TOA. TcO and ReO in the extracting phase were successfully stripped using neutral aqueous solutions as the receiving phase, and the extraction ability of HONTA was maintained after five repeated uses.
Oka, Toshitaka; Takahashi, Atsushi*; Koarai, Kazuma; Mitsuyasu, Yusuke*; Kino, Yasushi*; Sekine, Tsutomu*; Shimizu, Yoshinaka*; Chiba, Mirei*; Suzuki, Toshihiko*; Osaka, Ken*; et al.
Radiation Measurements, 134, p.106315_1 - 106315_4, 2020/06
Times Cited Count:5 Percentile:52.06(Nuclear Science & Technology)The relationship between the CO radical intensity and the absorbed dose (dose response curve) of tooth enamel of Japanese macaque was observed by electron spin resonance and the detection limit of our system was estimated to be 33.5 mGy, which is comparable to the detection limit for human molar teeth. Using the dose response curve, external exposure dose for seven wild Japanese macaques captured in Fukushima prefecture were examined. The results suggest that the external exposure dose for the wild Japanese macaques were ranged between 45 mGy to 300 mGy.