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Journal Articles

Estimation of external dose for wild Japanese macaques captured in Fukushima prefecture; Decomposition of electron spin resonance spectrum

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

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$$_{2}^{-}$$ radical intensity. We examined ESR spectra of teeth of 10 macaques captured in Fukushima by two spectrum-decomposition algorithms.

Journal Articles

A Study on accuracy of analysis of the radiation-induced component in the ESR spectra of teeth

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$$_{2}^{-}$$ radical.

Journal Articles

Detection limit of electron spin resonance for Japanese deciduous tooth enamel and density separation method for enamel-dentine separation

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:0 Percentile:29.28(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.

Journal Articles

Development of dose estimation method using wild animal teeth for low dose exposure

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.

Journal Articles

Rapid analysis of $$^{90}$$Sr in cattle bone and tooth samples by inductively coupled plasma mass spectrometry

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:3 Percentile:57.04(Chemistry, Analytical)

Rapid analysis of $$^{90}$$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 $$^{90}$$Sr in small bone and tooth samples derived from terrestrial animals.

Journal Articles

Radioactivity and radionuclides in deciduous teeth formed before the Fukushima-Daiichi Nuclear Power Plant accident

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:5 Percentile:42.99(Multidisciplinary Sciences)

Journal Articles

Speciation of cesium in tree tissues and its implication for uptake and translocation of radiocesium in tree bodies

Tanaka, Kazuya; Kanasashi, Tsutomu*; Takenaka, Chisato*; Takahashi, Yoshio*

Science of the Total Environment, 755(Part 2), p.142598_1 - 142598_8, 2021/02

 Times Cited Count:5 Percentile:36.59(Environmental Sciences)

In this study, we investigated coordination structures of Cs in $$^{133}$$Cs-doped bark, sapwood, heartwood, needle, and branch samples of trees collected in Fukushima by extended X-ray absorption fine structure (EXAFS) spectroscopy. We examined four representative tree species in Fukushima, ${it Cryptomeria japonica}$, ${it Pinus densiflora}$, ${it Quercus serrata}$, and ${it Eleutherococcus sciadophylloides}$. EXAFS spectra suggested that Cs was adsorbed as an outer-sphere complex on all parts of the four species, with electrostatic binding to negatively charged functional groups in components of tree tissues. These results were supported by extraction experiments where most of the sorbed Cs was desorbed from all parts of each tree species using 1 M CH$$_{3}$$COONH$$_{4}$$.

Journal Articles

A Sensitive method for Sr-90 analysis by accelerator mass spectrometry

Sasa, Kimikazu*; Honda, Maki; Hosoya, Seiji*; Takahashi, Tsutomu*; Takano, Kenta*; Ochiai, Yuta*; Sakaguchi, Aya*; Kurita, Saori*; Satou, Yukihiko; Sueki, Keisuke*

Journal of Nuclear Science and Technology, 58(1), p.72 - 79, 2021/01

 Times Cited Count:8 Percentile:72.51(Nuclear Science & Technology)

Journal Articles

External exposure dose estimation by electron spin resonance technique for wild Japanese macaque captured in Fukushima Prefecture

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:4 Percentile:54.54(Nuclear Science & Technology)

The relationship between the CO$$_{2}$$ 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.

Journal Articles

Sorption behavior of selenide on montmorillonite

Sugiura, Yuki; Tomura, Tsutomu*; Ishidera, Takamitsu; Doi, Reisuke; Francisco, P. C. M.; Shiwaku, Hideaki; Kobayashi, Toru; Matsumura, Daiju; Takahashi, Yoshio*; Tachi, Yukio

Journal of Radioanalytical and Nuclear Chemistry, 324(2), p.615 - 622, 2020/05

 Times Cited Count:3 Percentile:46.37(Chemistry, Analytical)

Journal Articles

Pre- and post-accident $$^{14}$$C activities in tree rings near the Fukushima Dai-ichi Nuclear Power Plant

Matsunaka, Tetsuya*; Sasa, Kimikazu*; Takahashi, Tsutomu*; Matsumura, Masumi*; Satou, Yukihiko; Shen, H.*; Sueki, Keisuke*; Matsuzaki, Hiroyuki*

Radiocarbon, 61(6), p.1633 - 1642, 2019/12

 Times Cited Count:2 Percentile:11.91(Geochemistry & Geophysics)

Journal Articles

Depth profile and inventory of $$^{36}$$Cl in soil near the Fukushima Dai-ichi Nuclear Power Plant

Ota, Yuki*; Sueki, Keisuke*; Sasa, Kimikazu*; Takahashi, Tsutomu*; Matsunaka, Tetsuya*; Matsumura, Masumi*; Tosaki, Yuki*; Honda, Maki*; Hosoya, Seiji*; Takano, Kenta*; et al.

JAEA-Conf 2018-002, p.99 - 102, 2019/02

no abstracts in English

Journal Articles

Radiocarbon variations in tree rings since 1960 near the Tokai nuclear facility, Japan

Matsunaka, Tetsuya*; Sasa, Kimikazu*; Takahashi, Tsutomu*; Hosoya, Seiji*; Matsumura, Masumi*; Satou, Yukihiko; Shen, H.*; Sueki, Keisuke*

Nuclear Instruments and Methods in Physics Research B, 439, p.64 - 69, 2019/01

 Times Cited Count:2 Percentile:23.44(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Quantum paramagnet near spin-state transition

Tomiyasu, Keisuke*; Ito, Naoko*; Okazaki, Ryuji*; Takahashi, Yuki*; Onodera, Mitsugi*; Iwasa, Kazuaki*; Nojima, Tsutomu*; Aoyama, Takuya*; Ogushi, Kenya*; Ishikawa, Yoshihisa*; et al.

Advanced Quantum Technologies (Internet), 1(3), p.1800057_1 - 1800057_7, 2018/12

Spin-state transition, also known as spin crossover, plays a key role in diverse systems. In theory, the boundary range between the low- and high-spin states is expected to enrich the transition and give rise to unusual physical states. However, no compound that realizes a nearly degenerate critical range as the ground state without requiring special external conditions has yet been experimentally identified. This study reports that the Sc substitution in LaCoO3 destabilizes its nonmagnetic low-spin state and generates an anomalous paramagnetic state accompanied by the enhancement of transport gap and magneto-lattice-expansion as well as the contraction of Co-O distance with the increase of electron site transfer. These phenomena are not well described by the mixture of conventional low- and high-spin states, but by their quantum superposition occurring on the verge of a spin-state transition.

Journal Articles

Application of the transient pulse method to measure clay permeability

Kato, Masaji*; Nara, Yoshitaka*; Okazaki, Yuki*; Kono, Masanori*; Sato, Toshinori; Sato, Tsutomu*; Takahashi, Manabu*

Materials Transactions, 59(9), p.1427 - 1432, 2018/09

 Times Cited Count:6 Percentile:33.02(Materials Science, Multidisciplinary)

To ensure the safe geological disposal of radioactive waste, it is important to determine the permeability (hydraulic conductivity) of clays. The transient pulse method is suitable for low-permeability materials because it requires a relatively short time to determine their permeability. Upstream pore pressure typically increases in the measurement conducted via the transient pulse method. However, this procedure cannot be used to determine the permeability of clays due to the increase in pore pressure. Therefore, the transient pulse method has never been applied to determine clay permeability. In this study, we applied the transient pulse method to a clay sample to determine its permeability while decreasing the downstream pore pressure.

Journal Articles

Evaluation of thermal strain induced in components of Nb$$_{3}$$Sn strand during cooling

Suwa, Tomone*; Hemmi, Tsutomu*; Saito, Toru*; Takahashi, Yoshikazu*; Koizumi, Norikiyo*; Luzin, V.*; Suzuki, Hiroshi; Harjo, S.

IEEE Transactions on Applied Superconductivity, 28(3), p.6001104_1 - 6001104_4, 2018/04

 Times Cited Count:1 Percentile:7.67(Engineering, Electrical & Electronic)

Journal Articles

Permeability of granite including macro-fracture naturally filled with fine-grained minerals

Nara, Yoshitaka*; Kato, Masaji*; Niri, Ryuhei*; Kono, Masanori*; Sato, Toshinori; Fukuda, Daisuke*; Sato, Tsutomu*; Takahashi, Manabu*

Pure and Applied Geophysics, 175(3), p.917 - 927, 2018/03

 Times Cited Count:12 Percentile:59.18(Geochemistry & Geophysics)

Information on the permeability of rock is essential for various geoengineering projects. It is especially important to investigate how fractures and pores influence the physical and transport properties of rock. Infiltration of groundwater through the damage zone fills fractures in granite with fine-grained minerals. However, the permeability of rock possessing a fracture naturally filled with fine-grained mineral grains has yet to be investigated. In this study, the permeabilities of granite samples, including a macro-fracture filled with clay and a mineral vein, are investigated. The permeability of granite with a fine-grained mineral vein agrees well with that of the intact sample, whereas the permeability of granite possessing a macro-fracture filled with clay is lower than that of the macro-fractured sample. The decrease in the permeability is due to the filling of fine-grained minerals and clay in the macro-fracture. It is concluded that the permeability of granite increases due to the existence of the fractures, but decreases upon filling them with fine-grained minerals.

Journal Articles

Application of transient pulse method to permeability measurement for clay

Kato, Masaji*; Nara, Yoshitaka*; Okazaki, Yuki*; Kono, Masanori*; Sato, Toshinori; Sato, Tsutomu*; Takahashi, Manabu*

Zairyo, 67(3), p.318 - 323, 2018/03

To ensure the safe geological disposal of radioactive wastes, it is important to determine the permeability of clays. The transient pulse test is suitable to apply to the low permeability materials, because it takes relatively short term to determine the permeability. Usually we increase the upstream pore pressure in the measurement with the transient pulse test. However, it is impossible to determine the permeability of clay in this procedure because of the increase of pore pressure. Therefore, the transient pulse test has never been applied to the determination of permeability of clays. In this study, we tried to apply the transient pulse test to a clay obtained in Mizunami Underground Research Laboratory to determine the permeability with decreasing the downstream pore pressure. It was clarified that the transient pulse test with decreasing downstream pore pressure is appropriate from the measurements of granite and sandstone. It was shown that the permeability of a clay was determined by the transient pulse test with decreasing the downstream pore pressure, which agreed with the permeability determined from the falling head test. The measurement time of the transient pulse test is much shorter than that of the falling head test. It is concluded that the transient pulse test is appropriate for the determination of the permeability of clays.

Journal Articles

Radiocarbon variations since 1960 in tree rings around the nuclear facilities of the eastern Japan

Matsunaka, Tetsuya*; Sasa, Kimikazu*; Takahashi, Tsutomu*; Hosoya, Seiji*; Matsumura, Masumi*; Sueki, Keisuke*; Satou, Yukihiko

Dai-19-Kai AMS Shimpojiumu, 2016-Nendo "Jumoku Nenrin" Kenkyukai Kyodo Kaisai Shimpojiumu Hokokushu, p.76 - 79, 2017/06

To evaluate the radiological impact of the atmospheric $$^{14}$$C discharge from the Tokai nuclear facilities, a 80-year-old Japanese pine tree from Tokai, 1.8 km south-southwest of the Tokai Nuclear Power Plants (Tokai NPP and Tokai-2 NPP) and 1.4 km North-Northwest of the Tokai Reprocessing Plant (Tokai RP), was cored and each annual ring was measured for $$^{14}$$C. The $$^{14}$$C specific activities varied from 232.8 Bq kg$$^{-1}$$ C to 403.3Bq kg$$^{-1}$$ C in the tree rings formed during the periods 1954-2013. The specific activities in 1967-2010 are significantly elevated compared with the ambient background values, clearly indicating $$^{14}$$C discharges from the nuclear facilities during their normal operation. The excess $$^{14}$$C activities of 0.5-70.0 Bq kg$$^{-1}$$ C in 1970-2011 are positively correlated with the estimated annual $$^{14}$$C discharges of 0.1-1.2 TBq from Tokai NPP and Tokai-2 NPP with R$$^{2}$$ of 0.66 (n = 38). These activity values of $$<$$ 70.0 Bq kg$$^{-1}$$ C were corresponding to an additional annual effective dose of $$<$$ 3.9 uSv via the food ingestion pathway in the study location.

Journal Articles

Importance of temperature control in surrounding environment during permeability test for measuring hydraulic constants of rock

Kato, Masaji*; Nara, Yoshitaka*; Fukuda, Daisuke*; Kono, Masanori*; Sato, Toshinori; Sato, Tsutomu*; Takahashi, Manabu*

Zairyo, 65(7), p.489 - 495, 2016/07

Rock masses serve a vital function as natural barriers for geological disposal of radioactive waste; therefore, information on rock permeability is essential. Highly accurate measurement of permeability requires understanding of how temperature changes in the surrounding environment influence measurement results. We performed permeability measurement under conditions with dramatic changes of temperature in the surrounding environment to investigate the influence of such changes on the experimental results. Measurement of permeability with no temperature change was also conducted as reference. All measurements were conducted using the transient pulse method, and the sample material used was Toki granite obtained from Gifu Prefecture in central Japan. We found that temperature changes in the surrounding environment remarkably affected the pressure in reservoirs upstream and downstream, the pressure difference between them, and the confining pressure; all increased when temperature increased for our experimental system. Notably, pressure difference was affected immediately. This difference directly relates to estimation of permeability.

135 (Records 1-20 displayed on this page)