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Journal Articles

The New 300 kV multi-element AMS system at the TONO Geoscience Center, Japan Atomic Energy Agency

Fujita, Natsuko; Miyake, Masayasu*; Matsubara, Akihiro; Kokubu, Yoko; Klein, M.*; Scognamiglio, G.*; Mous, D. J. W.*; Columna, E. L.*; Shimada, Akiomi; Ishimaru, Tsuneari

Nuclear Instruments and Methods in Physics Research B, 533, p.91 - 95, 2022/12

 Times Cited Count:0 Percentile:0.02(Instruments & Instrumentation)

In the Tono Geoscience Center, Japan Atomic Energy Agency, investigation of deep underground environments for R&D program related to the geological disposal of High-Level Radioactive Waste has been performed by using various dating systems including an AMS system. In response to the increasing demand for our AMS measurements especially from a newly established R&D program supporting development of technology for geological disposal of HLW, a state-of-the-art multi-nuclide AMS system was installed. This system is equipped with a 300 kV AMS. The system has capability to measure four nuclides: carbon-14, beryllium-10, aluminium-26 and iodine-129. The system structure and features, as well as the results of performance test will be presented.

Journal Articles

Project for development of a downsized AMS system based on the surface stripper technique

Fujita, Natsuko; Matsubara, Akihiro; Kimura, Kenji; Jinno, Satoshi; Kokubu, Yoko

Nuclear Instruments and Methods in Physics Research B, 532, p.13 - 18, 2022/12

 Times Cited Count:0 Percentile:0.02(Instruments & Instrumentation)

Over the last decade, significant technological advances were made to downsize the AMS systems. Japan Atomic Energy Agency has started a project for developing a prototype downsized AMS system (with the footprint of the system is 1.9 m $$times$$ 1.9 m) based on the surface stripper technique. Although the system configuration using an ion source, magnets, and detectors is similar to that in conventional systems, there is no tandem accelerator as well as a gas stripper. The ion acceleration is provided in the ion source (maximum ion energy 40 keV). For proof-of-principle experiments, we have planned two steps: (1) Observation of the specular reflection and the dissociation by using a compact electrostatic analyzer located just behind the stripper, and (2) Demonstration of $$^{14}$$C measurement, along with the experimental confirmation of the isobar suppression capability of the surface stripper.

JAEA Reports

Research plan on geosphere stability for long-term isolation of radioactive waste (Scientific program for fiscal year 2022)

Sasao, Eiji; Ishimaru, Tsuneari; Niwa, Masakazu; Shimada, Akiomi; Shimada, Koji; Watanabe, Takahiro; Sueoka, Shigeru; Yokoyama, Tatsunori; Fujita, Natsuko; Ogita, Yasuhiro; et al.

JAEA-Review 2022-022, 29 Pages, 2022/09

JAEA-Review-2022-022.pdf:0.97MB

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 2022. The objectives and contents in fiscal year 2022 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

JAEA Reports

Data comparison of measurement of carbon isotope standards between JAEA-AMS-TONO and JAEA-AMS-MUTSU

Kokubu, Yoko; Matsubara, Akihiro; Fujita, Natsuko; Kuwabara, Jun; Kinoshita, Naoki

JAEA-Technology 2021-028, 33 Pages, 2022/02

JAEA-Technology-2021-028.pdf:2.18MB

Japan Atomic Energy Agency (JAEA) has two facilities of accelerator mass spectrometry, JAEA-AMS-TONO and JAEA-AMS-MUTSU at Tono Geoscience Center and Aomori Research and Development Center, respectively. In this report, characteristics of each facility and results of standard samples in the inner-comparison test of carbon isotope measurement will be described. Both facilities have been used for research by not only JAEA's staff but also researchers who belong to universities and other institutes on the shared use program of JAEA facilities. Recently, researchers trend to use both facilities with the expansion of demand for the carbon isotope measurement by using the accelerator mass spectrometer (AMS). However, each facility has a spectrometer made by a different manufacturer and equipped with different mechanical components. There is a difference in each ability to the carbon isotope measurement such as background level. This is, for example, due to different ion injection system adapted at each spectrometer. Further, each facility uses a different analytical method adjusted to each main research field. When a researcher uses both facilities, the researcher understands more about the characteristics and need to make a suitable choice of a facility for samples and the analytical method. The report presents a detailed information of characteristics of the spectrometer, sample preparation method and analytical method, and of ability of the measurement based on the inner-comparison test.

JAEA Reports

Annual report for research on geosphere stability for long-term isolation of radioactive waste in fiscal year 2020

Ishimaru, Tsuneari; Ogata, Nobuhisa; Kokubu, Yoko; Shimada, Koji; Niwa, Masakazu; Shimada, Akiomi; Watanabe, Takahiro; Sueoka, Shigeru; Yokoyama, Tatsunori; Fujita, Natsuko; et al.

JAEA-Research 2021-007, 65 Pages, 2021/10

JAEA-Research-2021-007.pdf:4.21MB

This annual report documents the progress of research and development (R&D) in the 6th fiscal year during the JAEA 3rd Mid- and Long-term Plan (fiscal years 2015-2021) to provide the scientific base for assessing geosphere stability for long-term isolation of the high-level radioactive waste. The planned 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. The current status of R&D activities with previous scientific and technological progress is summarized.

Journal Articles

$$^{129}$$I/$$^{127}$$I and $$Delta$$$$^{14}$$C records in a modern coral from Rowley Shoals off northwestern Australia reflect the 20th-century human nuclear activities and ocean/atmosphere circulations

Mitsuguchi, Takehiro; Okabe, Nobuaki*; Yokoyama, Yusuke*; Yoneda, Minoru*; Shibata, Yasuyuki*; Fujita, Natsuko; Watanabe, Takahiro; Kokubu, Yoko

Journal of Environmental Radioactivity, 235-236, p.106593_1 - 106593_10, 2021/09

 Times Cited Count:1 Percentile:14.15(Environmental Sciences)

For a contribution to developing the usage of iodine-129 ($$^{129}$$I) as a tracer of deep-seated fluid, $$^{129}$$I/$$^{127}$$I and $$Delta$$$$^{14}$$C were measured for annual bands (AD 1931-1991) of a modern coral collected from Northwestern Australia; the measurements were performed using the JAEA-AMS-TONO-5MV for $$^{129}$$I/$$^{127}$$I and an AMS facility of the University of Tokyo for $$Delta$$$$^{14}$$C. Results indicate that both $$^{129}$$I/$$^{127}$$I and $$Delta$$$$^{14}$$C distinctly increase from 1950s. The $$Delta$$$$^{14}$$C increase can be ascribed to atmospheric nuclear tests, while the $$^{129}$$I/$$^{127}$$I increase is due to nuclear-fuel reprocessing as well as atmospheric nuclear tests. These results are in good agreement with previous studies, indicating that the $$^{129}$$I/$$^{127}$$I measurement by JAEA-AMS-TONO-5MV has been further developed.

JAEA Reports

Research plan on geosphere stability for long-term isolation of radioactive waste (Scientific program for fiscal year 2021)

Ishimaru, Tsuneari; Kokubu, Yoko; Shimada, Koji; Shimada, Akiomi; Niwa, Masakazu; Watanabe, Takahiro; Sueoka, Shigeru; Yokoyama, Tatsunori; Fujita, Natsuko; Ogita, Yasuhiro; et al.

JAEA-Review 2021-012, 48 Pages, 2021/08

JAEA-Review-2021-012.pdf:1.64MB

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 2021. The objectives and contents in fiscal year 2021 are described in detail based on the JAEA 3rd Medium- and Long-term Plan (fiscal years 2015-2021). 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.

Journal Articles

Formation process of swamp sediments of the Karako Lowland in northern Shimabara Peninsula, Western Japan

Nakanishi, Toshimichi*; Okuno, Mitsuru*; Yamasaki, Keiji*; Hong, W.*; Fujita, Natsuko; Nakamura, Toshio*; Horikawa, Yoshiyuki*; Sato, Eiichi*; Kimura, Haruo*; Tsutsumi, Hiroyuki*

Nagoya Daigaku Nendai Sokutei Kenkyu, 5, p.38 - 43, 2021/03

no abstracts in English

Journal Articles

Preliminary report on small-mass graphitization for radiocarbon dating using EA-AGE3 at JAEA-AMS-TONO

Watanabe, Takahiro; Fujita, Natsuko; Matsubara, Akihiro; Miyake, Masayasu*; Nishio, Tomohiro*; Ishizaka, Chika; Kokubu, Yoko

Geochemical Journal, 55(4), p.277 - 281, 2021/00

 Times Cited Count:1 Percentile:23.14(Geochemistry & Geophysics)

Small-mass radiocarbon dating less than 0.1 mg carbon has been developed by Accelerator mass spectrometry (AMS) and manual preparation techniques using the vacuum glass lines. Because geological samples are limited for the dating in many cases, preparation techniques should be improved for small samples and high efficiency analysis. For radiocarbon dating of geological and other organic samples, small-mass graphitization of international standard reference materials (ca. 0.1 and 0.05 mg carbon) was evaluated using the elemental analyzer and automated graphitization equipment 3 (EA-AGE3; IonPlus AG) in our study. Additionally, this paper presents the first data for the small samples by the EA-AGE3. The average radiocarbon concentration of the small-mass international standards (NIST-SRM4990C, IAEA-C5, and C7) prepared by the EA-AGE3 were agreement with the consensus values within $$pm$$ 2$$sigma$$. Therefore, small-mass graphitization using the EA-AGE3 can be adapted for AMS radiocarbon measurements in our case (down to ca. 0.05 mg carbon).

JAEA Reports

Practical guide on soil sampling, treatment, and carbon isotope analysis for carbon cycle studies

Koarashi, Jun; Atarashi-Andoh, Mariko; Nagano, Hirohiko*; Sugiharto, U.*; Saengkorakot, C.*; Suzuki, Takashi; Kokubu, Yoko; Fujita, Natsuko; Kinoshita, Naoki; Nagai, Haruyasu; et al.

JAEA-Technology 2020-012, 53 Pages, 2020/10

JAEA-Technology-2020-012.pdf:3.71MB

There is growing concern that recent rapid changes in climate and environment could have a significant influence on carbon cycling in terrestrial ecosystems (especially forest ecosystems) and could consequently lead to a positive feedback for global warming. The magnitude and timing of this feedback remain highly uncertain largely due to a lack of quantitative understanding of the dynamics of organic carbon stored in soils and its responses to changes in climate and environment. The tracing of radiocarbon (natural and bomb-derived $$^{14}$$C) and stable carbon ($$^{13}$$C) isotopes through terrestrial ecosystems can be a powerful tool for studying soil organic carbon (SOC) dynamics. The primary aim of this guide is to promote the use of isotope-based approaches to improve our understanding of the carbon cycling in soils, particularly in the Asian region. The guide covers practical methods of soil sampling; treatment and fractionation of soil samples; preparation of soil samples for $$^{13}$$C (and stable nitrogen isotope, $$^{15}$$N) and $$^{14}$$C analyses; and $$^{13}$$C, $$^{15}$$N, and $$^{14}$$C measurements by the use of isotope ratio mass spectrometry and accelerator mass spectrometry (AMS). The guide briefly introduces ways to report $$^{14}$$C data, which are frequently used for soil carbon cycling studies. The guide also reports results of a case study conducted in a Japanese forest ecosystem, as a practical application of the use of isotope-based approaches. This guide is mainly intended for researchers who are interested but are not experienced in this research field. The guide will hopefully encourage readers to participate in soil carbon cycling studies, including field works, laboratory experiments, isotope analyses, and discussions with great interest.

JAEA Reports

Annual report for research on geosphere stability for long-term isolation of radioactive waste in fiscal year 2019

Ishimaru, Tsuneari; Ogata, Nobuhisa; Kokubu, Yoko; Shimada, Koji; Hanamuro, Takahiro; Shimada, Akiomi; Niwa, Masakazu; Asamori, Koichi; Watanabe, Takahiro; Sueoka, Shigeru; et al.

JAEA-Research 2020-011, 67 Pages, 2020/10

JAEA-Research-2020-011.pdf:3.87MB

This annual report documents the progress of research and development (R&D) in the 5th fiscal year during the JAEA 3rd Mid- and Long-term Plan (fiscal years 2015-2021) to provide the scientific base for assessing geosphere stability for long-term isolation of the high-level radioactive waste. The planned 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. The current status of R&D activities with previous scientific and technological progress is summarized.

JAEA Reports

Research plan on geosphere stability for long-term isolation of radioactive waste (Scientific program for fiscal year 2020)

Ishimaru, Tsuneari; Ogata, Nobuhisa; Shimada, Koji; Kokubu, Yoko; Niwa, Masakazu; Asamori, Koichi; Watanabe, Takahiro; Sueoka, Shigeru; Komatsu, Tetsuya; Yokoyama, Tatsunori; et al.

JAEA-Review 2020-010, 46 Pages, 2020/07

JAEA-Review-2020-010.pdf:1.89MB

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 2020. The objectives and contents in fiscal year 2020 are described in detail based on the JAEA 3rd Medium- and Long-term Plan (fiscal years 2015-2021). 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.

Journal Articles

Application of ion channeling for downsizing Accelerator Mass Spectrometry (AMS) systems

Matsubara, Akihiro*; Fujita, Natsuko; Ishii, Kunikazu*; Kimura, Kenji*

Hoshasen (Internet), 45(3), p.134 - 138, 2020/04

no abstracts in English

Journal Articles

Radiocarbon dating of a shrine pavilion and offerings at Abushina shrine in Gifu prefecture, Japan

Kokubu, Yoko; Nishio, Tomohiro; Fujita, Natsuko; Matsubara, Akihiro

Proceedings of the 8th East Asia Accelerator Mass Spectrometry Symposium and the 22nd Japan Accelerator Mass Spectrometry symposium (EA-AMS 8 & JAMS-22), p.91 - 93, 2020/00

no abstracts in English

Journal Articles

Present status of the JAEA-AMS-TONO in 2019

Fujita, Natsuko; Matsubara, Akihiro; Miyake, Masayasu*; Watanabe, Takahiro; Kokubu, Yoko; Kato, Motohisa*; Okabe, Nobuaki*; Isozaki, Nobuhiro*; Ishizaka, Chika*; Nishio, Tomohiro; et al.

Proceedings of the 8th East Asia Accelerator Mass Spectrometry Symposium and the 22nd Japan Accelerator Mass Spectrometry symposium (EA-AMS 8 & JAMS-22), p.34 - 36, 2020/00

no abstracts in English

Journal Articles

A Study of surface stripper for the AMS system with a footprint below 2 m $$times$$ 2 m

Matsubara, Akihiro; Fujita, Natsuko; Kimura, Kenji

Proceedings of the 8th East Asia Accelerator Mass Spectrometry Symposium and the 22nd Japan Accelerator Mass Spectrometry symposium (EA-AMS 8 & JAMS-22), p.57 - 59, 2020/00

no abstracts in English

JAEA Reports

Annual report for research on geosphere stability for long-term isolation of radioactive waste in fiscal year 2018

Ishimaru, Tsuneari; Ogata, Nobuhisa; Hanamuro, Takahiro; Shimada, Akiomi; Kokubu, Yoko; Asamori, Koichi; Niwa, Masakazu; Shimada, Koji; Watanabe, Takahiro; Saiga, Atsushi; et al.

JAEA-Research 2019-006, 66 Pages, 2019/11

JAEA-Research-2019-006.pdf:4.39MB

This annual report documents the progress of research and development (R&D) in the 4th fiscal year during the JAEA 3rd Mid- and Long-term Plan (fiscal years 2015-2021) to provide the scientific base for assessing geosphere stability for long-term isolation of the high-level radioactive waste. The planned 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. In this report, the current status of R&D activities with previous scientific and technological progress is summarized.

Journal Articles

Current status of JAEA-AMS-TONO in the 20th year

Kokubu, Yoko; Fujita, Natsuko; Miyake, Masayasu; Watanabe, Takahiro; Ishizaka, Chika; Okabe, Nobuaki; Ishimaru, Tsuneari; Matsubara, Akihiro*; Nishizawa, Akimitsu*; Nishio, Tomohiro*; et al.

Nuclear Instruments and Methods in Physics Research B, 456, p.271 - 275, 2019/10

 Times Cited Count:2 Percentile:27.72(Instruments & Instrumentation)

JAEA-AMS-TONO has been in operation at the Tono Geoscience Center, Japan Atomic Energy Agency since 1998 and 20 years have passed from the beginning of its utilization. The AMS system is a versatile system based on a 5 MV tandem Pelletron type accelerator. The system has been used to measure carbon-14 ($$^{14}$$C), beryllium-10 ($$^{10}$$Be) and aluminium-26 ($$^{26}$$Al). In addition, the development of measurement of iodine-129 ($$^{129}$$I) has been started. The main use is measurement of $$^{14}$$C in geological samples for dating studies in neotectonics and hydrogeology. In order to increase the speed of sample preparation, we introduced the automated graphitization equipment and made a gas-strip line to collect dissolved inorganic carbon in groundwater samples. Measurement of $$^{10}$$Be and $$^{26}$$Al has been used for geoscience studies and the detection limit in the measurement of $$^{10}$$Be was improved by $$^{7}$$Be-counting suppression. Recently tuning of measurement condition of $$^{129}$$I has been progressed.

JAEA Reports

Research plan on geosphere stability for long-term isolation of radioactive waste (Scientific program for fiscal year 2019)

Ishimaru, Tsuneari; Ogata, Nobuhisa; Hanamuro, Takahiro; Shimada, Akiomi; Kokubu, Yoko; Asamori, Koichi; Niwa, Masakazu; Shimada, Koji; Watanabe, Takahiro; Sueoka, Shigeru; et al.

JAEA-Review 2019-010, 46 Pages, 2019/09

JAEA-Review-2019-010.pdf:2.45MB

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, in fiscal year 2019. The objectives and contents in fiscal year 2019 are described in detail based on the outline of 7 years plan (fiscal years 2015-2021). Background of this research is clarified with the necessity and the significance for site investigation and safety assessment, and the past progress in this report. In addition, 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.

JAEA Reports

Annual report for research on geosphere stability for long-term isolation of radioactive waste in fiscal year 2017

Ishimaru, Tsuneari; Ogata, Nobuhisa; Shimada, Akiomi; Asamori, Koichi; Kokubu, Yoko; Niwa, Masakazu; Watanabe, Takahiro; Saiga, Atsushi; Sueoka, Shigeru; Komatsu, Tetsuya; et al.

JAEA-Research 2018-015, 89 Pages, 2019/03

JAEA-Research-2018-015.pdf:14.43MB

This annual report documents the progress of research and development (R&D) in the 3rd fiscal year during the JAEA 3rd Mid- and Long-term Plan (fiscal years 2015-2021) to provide the scientific base for assessing geosphere stability for long-term isolation of the high-level radioactive waste. The planned 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. In this report, the current status of R&D activities with previous scientific and technological progress is summarized.

112 (Records 1-20 displayed on this page)