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Minami, Saki*; Sueoka, Shigeru; Malatesta, L. C.*; Fukuda, Shoma; Tagami, Takahiro*
Fuisshon, Torakku Nyusureta, (38), p.26 - 30, 2025/12
no abstracts in English
Asamori, Koichi; Sueoka, Shigeru; Komatsu, Tetsuya; Ogata, Manabu; Uchida, Mao; Nishiyama, Nariaki; Tanaka, Kiriha; Kobayashi, Tomoharu; Mitsuguchi, Takehiro; Murakami, Osamu; et al.
JAEA-Review 2025-035, 29 Pages, 2025/10
JAEA-Review-2025-035.pdf:1.12MB
This report is a plan of research and development (R&D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in Japan Atomic Energy Agency (JAEA), in fiscal year 2025. The objectives and contents of this research are described in detail based on the JAEA 4th Medium- and Long-term Plan (fiscal years 2022-2028). In addition, the background of this research is described from the necessity and the significance for site investigation and safety assessment, and the past progress. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.
Chiu, I.-H.; Osawa, Takahito; Sumita, Takehiro*; Ikeda, Mizuha*; Ninomiya, Kazuhiko*; Takeda, Shinichiro*; Minami, Takahiro*; Takahashi, Tadayuki*; Watanabe, Shin*
Applied Radiation and Isotopes, 222, p.111845_1 - 111845_7, 2025/08
Times Cited Count：2 Percentile：65.74(Chemistry, Inorganic & Nuclear)
in downwind East AsiaNozomu, Tsuchiya*; Ikemori, Fumikazu*; Kawasaki, Kazuo*; Yamada, Rena*; Hata, Mitsuhiko*; Furuuchi, Masami*; Iwamoto, Yoko*; Kaneyasu, Naoki*; Sadanaga, Yasuhiro*; Watanabe, Takahiro; et al.
Environmental Science & Technology, 59(21), p.10400 - 10410, 2025/05
Times Cited Count：2 Percentile：43.74(Engineering, Environmental)Black carbon (BC) is a typical primary aerosol emitted from combustion. While its co-existence with iron oxides (FeO
) has recently been reported, the extent of bias caused by FeO mixing to the BC observations is largely unknown. To identify the dominant FeO emission sources and associated overestimation of BC, magnetics properties of PM collected at a remote site in East Asia was investigated in combination with detailed isotopic and chemical analyses. Consequently, biomass burning events did not enhance aerosol magnetism as they did for the mass concentration of BC, whereas coal burning events coincided with periods of high magnetization. Therefore, magnetization/BC ratio is proposed as a highly selective indicator for identifying combustion sources (i.e. coal, oil or biomass burning).
Osawa, Takahito; Nagasawa, Shunsaku*; Ninomiya, Kazuhiko*; Takahashi, Tadayuki*; Nakamura, Tomoki*; Wada, Taiga*; Taniguchi, Akihiro*; Umegaki, Izumi*; Kubo, Kenya*; Terada, Kentaro*; et al.
ACS Earth and Space Chemistry (Internet), 7(4), p.699 - 711, 2023/04
Times Cited Count：9 Percentile：62.45(Chemistry, Multidisciplinary)The concentrations of carbon and other major elements in asteroid samples provide very important information on the birth of life on the Earth and the solar-system evolution. Elemental analysis using muonic X-rays is one of the best analytical methods to determine the elemental composition of solid materials, and notably, is the only method to determine the concentration of light elements in bulk samples in a non-destructive manner. We developed a new analysis system using muonic X-rays to measure the concentrations of carbon and other major elements in precious and expectedly tiny samples recovered from the asteroid Ryugu by spacecraft Hayabusa2. Here we report the development process of the system in 4 stages and their system configurations, The analysis system is composed of a stainless-steel analysis chamber, an acrylic glove box for manipulating asteroid samples in a clean environment, and Ge semiconductor detectors arranged to surround the analysis chamber. The performance of the analysis system, including the background level, which is crucial for the measurement, was greatly improved from the first stage to the later ones. Our feasibility study showed that the latest model of our muonic X-ray analysis system is capable of determining the carbon concentration in Hayabusa2's sample model with an uncertainty of less than 10 percent in a 6-day measurement.
Minami, Saki*; Sueoka, Shigeru; Fukuda, Shoma; Nagata, Mitsuhiro; Kohn, B. P.*; Yokoyama, Tatsunori; Kagami, Saya; Kajita, Yuya*; Tagami, Takahiro*
Fuisshon, Torakku Nyusureta, (35), p.22 - 26, 2022/12
no abstracts in English
Nagata, Mitsuhiro; Fukuda, Shoma; Sueoka, Shigeru; Nakajima, Toru; Kajita, Yuya*; Minami, Saki*; Okamoto, Akira*; Tagami, Takahiro*
Fuisshon, Torakku Nyusureta, (35), p.15 - 18, 2022/09
We performed U-Pb dating on zircons from the Utaosa Rhyolite of the Teragi Group as part of the search for standard materials for dating of zircons. Previous studies about Utaosa Rhyolite have reported ca. 2.30-2.77 Ma zircon fission track, zircon (U-Th)/He, and biotite K-Ar ages. U-Pb dating was carried out on the multi-collector inductively coupled plasma mass spectrometer with a laser ablation system. The weighted mean 
U-
Pb ages of 2.65
0.16 Ma and 2.660.15 Ma were obtained from two samples. These ages are consistent with the ages from the previous studies. Therefore the results show that zircons from the Utaosa Rhyolite may be effective as a standard material.
Minami, Saki*; Nagata, Mitsuhiro; Sueoka, Shigeru; Fukuda, Shoma; Kajita, Yuya*; Ogita, Yasuhiro; Kagami, Saya; Yokoyama, Tatsunori; Tagami, Takahiro*
Earth, Planets and Space (Internet), 73(1), p.231_1 - 231_7, 2021/12
Times Cited Count：3 Percentile：6.81(Geosciences, Multidisciplinary)Minami, Saki*; Nagata, Mitsuhiro; Sueoka, Shigeru; Fukuda, Shoma; Kajita, Yuya*; Ogita, Yasuhiro; Yokoyama, Tatsunori; Kagami, Saya; Tagami, Takahiro*
Fuisshon, Torakku Nyusureta, (34), p.4 - 8, 2021/12
This study employed U-Pb dating for determining the intrusive age of young (several Ma) granitoids in Tanigawa-dake area, where rapid and intense uplift/denudation has probably occurred in Japan. As results, U-Pb age of 109 Ma for the Cretaceous granodiorite and 3.95-3.19 Ma about 3 samples of the Pliocene granodiorites were obtained. These U-Pb ages showed consistent with previously reported ages based on thermochronometers having lower closure temperatures such as K-Ar or zircon fission-track methods. All previous data indicated younger ages than U-Pb ones in this study. Therefore, our U-Pb data can be interpreted as intrusive ages of young granitoids, inferring multiple events possibly occurred at least twice and contributed to the formation in young granitoids in the Tanigawa-dake area.
Nara, Fumiko*; Yokoyama, Tatsunori; Yamasaki, Shinichi*; Minami, Masayo*; Asahara, Yoshihiro*; Watanabe, Takahiro; Yamada, Kazuyoshi*; Tsuchiya, Noriyoshi*; Yasuda, Yoshinori*
Geochemical Journal, 55(3), p.117 - 133, 2021/00
Times Cited Count：6 Percentile：30.31(Geochemistry & Geophysics)The absolute date of the Millennium Eruption (ME) of Changbaishan Volcano is widely recognized as AD 946. The Baegdosan-Tomakomai (B-Tm) tephra dispersed during the ME is a robust-age key bed. In order to identify the tephra, refractive index and major-element compositions of volcanic glass shards are conventionally used. However, trace-element analysis has been rarely carried out, especially for rare-earth elements (REEs) and for tephra layer bulk sediments. Here we present the datasets of major- and trace-element compositions datasets for the glass shards and bulk sediments of the B-Tm and Towada caldera eruptions (To-a) tephra deposits from the Lake Ogawara sediment core, Tohoku region, northern Japan. The depth profiles of the major and trace elements show the significant peaks for the K
O and some trace elements (Zn, Rb, Zr, Nb, Sn, Y, La, Ce, Nd, Th, and U) at the B-Tm tephra layer in the Lake Ogawara sediment core, but no peaks of these elements at the To-a tephra layer. High concentrations of the trace elements in the B-Tm tephra layer were observed in individual glass shards as well as in the bulk sediment. These concentrations are highlighted by the elemental abundance pattern normalized by the crustal abundance. The elemental pattern in individual glass shards from other Japanese tephras showed significant differences from those of the B-Tm tephra, especially in REEs compositions. The trace-element compositions of the glass shards and bulk sediment show strong advantages for distinguishing the B-Tm tephra from other Japanese tephras.
Minami, Takahiro; Suzuki, Yoshio; Aoyagi, Tetsuo; Ito, Toshinori*; Nakajima, Norihiro
FAPIG, (174), p.31 - 39, 2007/02
The Center for Computational Science and E-systems of the Japan Atomic Energy Agency (CCSE/JAEA) has started a program to construct an international computational infrastructure in atomic energy research field called the AEGIS (Atomic Energy Grid InfraStructure) in April, 2006. The development is based on numerous experiences and technologies acquired from the development of the STA (Seamless Thinking Aid) and the ITBL (Information Technology Based Laboratory) infrastructure software. In this paper, we will introduce two key achievements prior to the AEGIS program: "Interoperable system between UNICORE in Germany and ITBL" which achieves international sharing of computational resources, and the "STARPC Plus" which can construct a compact grid system.
Kushida, Noriyuki; Suzuki, Yoshio; Minami, Takahiro; Aoyagi, Tetsuo; Nakajima, Norihiro
Zen NEC C&C Shisutemu Yuzakai Heisei-19-Nendo Rombunshu (CD-ROM), 10 Pages, 2007/00
Interoperability establishment between two different GRIDs.
Suzuki, Yoshio; Minami, Takahiro; Tani, Masayuki; Nakajima, Norihiro; Keller, R.*; Beisel, T.*
Proceedings of 7th International Meeting on High Performance Computing for Computational Science (VECPAR '06)/Workshop on Computational Grids and Clusters (WCGC '06) (CD-ROM), 9 Pages, 2006/07
The interoperability among different science grid systems is indispensable to worldwide use of a large-scale experimental facility as well as a large-scale supercomputer. One of the simplest ways to achieve the interoperability is to convert messages among different science grid systems without modifying themselves. Under such consideration, the interoperability between UNICORE and ITBL (IT-Based Laboratory) has been achieved with hardly modifying these grid systems by adopting a connection server which works as a mediator. Until international standardization is established, the method of message conversion among different science grid systems is promising as a way to establish the interoperability.
Minami, Saki*; Sueoka, Shigeru; Kohn, B. P.*; Fukuda, Shoma; Kajita, Yuya*; Ogita, Yasuhiro; Tagami, Takahiro*
no journal, ,
no abstracts in English
Kushida, Noriyuki; Suzuki, Yoshio; Minami, Takahiro; Tani, Masayuki; Nakajima, Norihiro; Keller, R.*; Beisel, T.*
no journal, ,
no abstracts in English
Suzuki, Yoshio; Kushida, Noriyuki; Yamagishi, Nobuhiro; Minami, Takahiro; Matsumoto, Nobuko; Nakajima, Kohei; Nishida, Akemi; Matsubara, Hitoshi; Tian, R.; Hazama, Osamu; et al.
no journal, ,
no abstracts in English
from Noto peninsular in Kanazawa, JapanYamada, Rena*; Ikemori, Fumikazu*; Nakamura, Toshio*; Minami, Masayo*; Watanabe, Takahiro; Kinouchi, Kento*; Matsuki, Atsushi*
no journal, ,
PM is becoming the focus of international attention, particularly in eastern Asia, because of air pollution and the health risks. Carbon is one of the major components in aerosol. Therefore, sources of the carbon compound should be known for the understanding material cycles and mechanism of the rise. Radiocarbon analysis is unique and useful techniques for estimation of carbon sources in environmental samples including aerosol. Hence half-life of radiocarbon is 5730 years, percent modern carbon (pMC) value based on radiocarbon concentration of fossil fuels are negligible. Therefore, pMC value can reveal the components of carbon in aerosol (biomass carbon versus fossil fuel). In this study, aerosol samples were taken at Noto Peninsula in Ishikawa pref., Japan, in order to estimate contribution rate of biomass carbon and/or fossil fuel in PM. The pMC values of PM at Noto were more than 70 in the summer of 2014. These results show that biomass contribution is relative high in the area.
Matsubara, Hitoshi; Minami, Takahiro; Hazama, Osamu; Nishida, Akemi; Tian, R.; Nakajima, Norihiro; Tani, Masayuki
no journal, ,
A nuclear power plant is made up of numerous components. In previous techniques, structural analyses of entire nuclear power plant have not been achieved because it is assumed to be united structure. In this work, through our new model approach called the assembled-structure analysis, simulation of an entire nuclear power plant by assembling of individual components was made possible.
Tsuchiya, Nozomu*; Ikemori, Fumikazu*; Kawasaki, Kazuo*; Yamada, Rena*; Hata, Mitsuhiko*; Furuuchi, Masami*; Iwamoto, Yoko*; Kaneyasu, Naoki*; Watanabe, Takahiro; Kameda, Takayuki*; et al.
no journal, ,
It is important to assess the impact of iron oxide aerosols, e.g. from fossil fuel combustion, on climate change. However, observations of iron oxide aerosols are limited worldwide and knowledge on their behavior in the environment is insufficient. Therefore, this study attempted to elucidate the sources of combustion-derived iron oxides (coal, oil and biomass) and their seasonal variations by measuring magnetization, radiocarbon and stable carbon isotope ratios, black carbon and elemental carbon concentrations in aerosol samples collected in the Noto region, a downwind region of East Asia.
Chiu, I.-H.; Osawa, Takahito; Sumita, Takehiro*; Ikeda, Mizuha*; Ninomiya, Kazuhiko*; Takeda, Shinichiro*; Takahashi, Tadayuki*; Minami, Takahiro*; Watanabe, Shin*
no journal, ,
Boron neutron capture therapy (BNCT) is a cancer treatment method that uses neutrons. After administering a boron drug that has the property of collecting in cancer cells to the human body, the affected area is irradiated with neutrons, and the generated alpha rays selectively destroy the cancer cells. To confirm the effectiveness of the treatment, it is extremely important to accurately confirm the area where boron reacts with neutrons. Therefore, we investigated the possibility of applying BNCT-SPECT using a CdTe double-sided strip-type detector. The CdTe-DSD is a comma-ray two-dimensional imaging detector that combines a high energy resolution of several keV with a FWHM of several hundred keV and a spatial resolution of 250 micro-m. By utilizing such high resolution of the detector, the prompt gamma rays originating from boron that causes a nuclear reaction can be detected, and the localization location of boron can be precisely identified. In this study, the CdTe-DSD was combined with a pinhole collimator to evaluate the boron distribution in solid samples in the research reactor JRR-3 of the Japan Atomic Energy Agency. The sample weighed 8.86 mg and contained 0.3 mg of boron. The figure shows the energy spectrum measured in this experiment and an image in the boron signal region. A circular boron projection image with a diameter of 11.5 mm was successfully obtained. The boron count rate was 0.115 cps and the signal-to-noise ratio was about 0.25. These results indicate that the CdTe-DSD has the potential to contribute to the development of BNCT-SPECT.
