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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

https://doi.org/10.1016/j.jenvrad.2021.106593
 Times Cited Count：5 Percentile：35.21(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.

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

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

https://doi.org/10.1016/j.nimb.2019.03.015
 Times Cited Count：5 Percentile：48.99(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.

Journal Articles

Improvement of methods for measurement of $$^{129}$$I/$$^{127}$$I ratio at JAEA-AMS-TONO

Okabe, Nobuaki; Fujita, Natsuko; Matsubara, Akihiro*; Miyake, Masayasu; Nishio, Tomohiro*; Nishizawa, Akimitsu*; Isozaki, Nobuhiro*; Watanabe, Takahiro; Kokubu, Yoko

JAEA-Conf 2018-002, p.51 - 54, 2019/02

https://doi.org/10.11484/jaea-conf-2018-002

no abstracts in English

Journal Articles

The Twenty years of JAEA-AMS-TONO

Kokubu, Yoko; Fujita, Natsuko; Matsubara, Akihiro*; Nishizawa, Akimitsu*; Nishio, Tomohiro; Miyake, Masayasu; Ishimaru, Tsuneari; Watanabe, Takahiro; Ogata, Nobuhisa; Shimada, Akiomi; et al.

JAEA-Conf 2018-002, p.5 - 8, 2019/02

https://doi.org/10.11484/jaea-conf-2018-002

no abstracts in English

Journal Articles

Present status of the accelerator facility at the JAEA-AMS-TONO; 2017

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

Dai-31-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.92 - 95, 2018/12

no abstracts in English

Oral presentation

Present status of AMS $$^{129}$$I/$$^{127}$$I measurement at the JAEA-AMS-TONO

Fujita, Natsuko; Okabe, Nobuaki; Matsubara, Akihiro*; Miyake, Masayasu; Nishio, Tomohiro*; Nishizawa, Akimitsu*; Isozaki, Nobuhiro*; Watanabe, Takahiro; Kokubu, Yoko

no journal, , 

no abstracts in English

Oral presentation

Preparation methods for measurement of $$^{129}$$I/$$^{127}$$I ratio and present status of JAEA-AMS-TONO

Okabe, Nobuaki; Fujita, Natsuko; Watanabe, Takahiro; Kokubu, Yoko

no journal, , 

no abstracts in English

Oral presentation

Present status of $$^{129}$$I/$$^{127}$$I measurement at the JAEA-AMS-TONO

Miyake, Masayasu; Fujita, Natsuko; Okabe, Nobuaki; Kokubu, Yoko; Shimada, Akiomi; Ogata, Nobuhisa

no journal, , 

no abstracts in English

Oral presentation

Research and development with accelerator mass spectrometer at Tono Geoscience Center, Japan Atomic Energy Agency (JAEA-AMS-TONO)

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

no journal, , 

no abstracts in English

Oral presentation

Construction of measurement procedure of $$^{129}$$I/$$^{127}$$I ratio in underground water by accelerator mass spectrometry at Tono Geoscience Center, Japan Atomic Energy Agency

Fujita, Natsuko; Okabe, Nobuaki*; Matsubara, Akihiro; Miyake, Masayasu*; Kokubu, Yoko; Watanabe, Takahiro

no journal, , 

no abstracts in English

Oral presentation

Preliminary test for $$^{129}$$I measurement of CaCO$$_{3}$$ samples in JAEA-AMS-TONO

Mitsuguchi, Takehiro; Okabe, Nobuaki*; Miyake, Masayasu*; Matsubara, Akihiro; Fujita, Natsuko; Watanabe, Takahiro; Kokubu, Yoko

no journal, , 

A preliminary test for AMS $$^{129}$$I measurement of CaCO$$_{3}$$ samples was performed using a tandem Pelletron AMS system at Tono Geoscience Center, Japan Atomic Energy Agency (JAEA-AMS-TONO). An annually-banded coral collected from Vietnam was used for this test. The procedure of the test was as follows: (1) an annual-band sample of AD 1946-47 from the coral was treated with 1% HCl for removal of its surface portion; (2) the treated sample was dissolved in H$$_{3}$$PO$$_{4}$$ solution; (3) an aliquot from the sample solution was used for $$^{127}$$I measurement by ICP-MS; (4) the Woodward iodine standard was added as a carrier to the sample solution; (5) iodine was extracted from the solution by solvent extraction and back-extraction, resulting in an aqueous phase with extracted iodine; (6) AgNO$$_{3}$$(aq) was added to the aqueous phase to obtain AgI precipitate; (7) the AgI precipitate was mixed with Nb and pressed into a copper cathode for $$^{129}$$I measurement by JAEA-AMS-TONO. A blank test of this procedure was also made to evaluate the background $$^{129}$$I effect in the sample preparation. Results we obtained were as follows: (1) the background $$^{129}$$I/$$^{127}$$I ratio was [4.3 $$pm$$ 0.1] $$times$$ 10$$^{-14}$$ and (2) the background-corrected coral $$^{129}$$I/$$^{127}$$I ratio was [1.53 $$pm$$ 0.76] $$times$$ 10$$^{-12}$$. The coral $$^{129}$$I/$$^{127}$$I ratio is generally in agreement with previously-reported values of Chang et al. (2016), suggesting that AMS $$^{129}$$I measurement of CaCO$$_{3}$$ samples has been generally established in JAEA-AMS-TONO.

Oral presentation

Research and development for accelerator mass spectrometer at JAEA-AMS-TONO

Fujita, Natsuko; Matsubara, Akihiro; Miyake, Masayasu*; Okabe, Nobuaki*; Nishio, Tomohiro*; Kimura, Kenji; Watanabe, Takahiro; Kokubu, Yoko

no journal, , 

no abstracts in English

13 (Records 1-13 displayed on this page)
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