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Journal Articles

Chemical characterization of a volatile dubnium compound, DbOCl$$_3$$

Chiera, N. M.*; Sato, Tetsuya; Eichler, R.*; Tomitsuka, Tomohiro; Asai, Masato; Adachi, Sadia*; Dressler, R.*; Hirose, Kentaro; Inoue, Hiroki*; Ito, Yuta; et al.

Angewandte Chemie; International Edition, 60(33), p.17871 - 17874, 2021/08

 Times Cited Count:0 Percentile:0(Chemistry, Multidisciplinary)

The formation and the chemical characterization of single atoms of dubnium (Db, element 105), in the form of its volatile oxychloride, was investigated using the on-line gas phase chromatography technique, in the temperature range 350 - 600 $$^circ$$C. Under the exact same chemical conditions, comparative studies with the lighter homologs of group-5 in the Periodic Table clearly indicate the volatility sequence being NbOCl$$_3 > $$ TaOCl$$_3 geq$$ DbOCl$$_3$$. From the obtained experimental results, thermochemical data for DbOCl$$_3$$ were derived. The present study delivers reliable experimental information for theoretical calculations on the chemical properties of transactinides.

Journal Articles

Quasifree neutron knockout reaction reveals a small $$s$$-Orbital component in the Borromean nucleus $$^{17}$$B

Yang, Z. H.*; Kubota, Yuki*; Corsi, A.*; Yoshida, Kazuki; Sun, X.-X.*; Li, J. G.*; Kimura, Masaaki*; Michel, N.*; Ogata, Kazuyuki*; Yuan, C. X.*; et al.

Physical Review Letters, 126(8), p.082501_1 - 082501_8, 2021/02

 Times Cited Count:10 Percentile:98.7(Physics, Multidisciplinary)

A quasifree ($$p$$,$$pn$$) experiment was performed to study the structure of the Borromean nucleus $$^{17}$$B, which had long been considered to have a neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for $$1s_{1/2}$$ and $$0d_{5/2}$$ orbitals, and a surprisingly small percentage of 9(2)% was determined for $$1s_{1/2}$$. Our finding of such a small $$1s_{1/2}$$ component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in $$^{17}$$B. The present work gives the smallest $$s$$- or $$p$$-orbital component among known nuclei exhibiting halo features and implies that the dominant occupation of $$s$$ or $$p$$ orbitals is not a prerequisite for the occurrence of a neutron halo.

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:0 Percentile:0.01(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).

Journal Articles

Synchronized gravitational slope deformation and active faulting; A Case study on and around the Neodani fault, central Japan

Komura, Keitaro*; Kaneda, Heitaro*; Tanaka, Tomoki*; Kojima, Satoru*; Inoue, Tsutomu*; Nishio, Tomohiro

Geomorphology, 365, p.107214_1 - 107214_22, 2020/09

 Times Cited Count:0 Percentile:0.01(Geography, Physical)

On the basis of pit excavations and sediment cores at an off-fault deep-seated gravitational slope deformation (DGSD) site and a trench excavation across the active Neodani fault at a nearby site, we examined the records of DGSD and surface-rupturing paleoearthquakes of the Neodani fault. We found the four most recent DGSD events and the four most recent surface-rupturing earthquakes, respectively and conclude that the ages of events are overlapped each other. We infer that static crustal strain from repeated seismogenic faulting plays an important role in the occurrence of DGSD events, at least in the immediate vicinity of active faults, although coseismic severe shaking would have at least some effect on them. Our case study suggests that off-fault DGSDs can be used to reconstruct or refine the paleoseismic history of a nearby active fault.

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

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:1 Percentile:23.13(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

The present status of the AGE3 automated graphitization equipment for radiocarbon dating at the JAEA-AMS-TONO

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

JAEA-Conf 2018-002, p.116 - 119, 2019/02

AMS is widely used for radiocarbon dating of geological samples. However, improvement in efficiency of sample preparation techniques are needed for high-time resolution dataset. In 2016, automated graphitization equipment (AGE3, IonPlus AG) has been installed in Toki Research Institute of Isotope Geology and Geochronology, Tono Geoscience Center, JAEA. Background values and carbon recovery rates during preparation process of AGE3 should be estimated before application in radiocarbon dating. In this study, the AGE3 system was evaluated using the international standard materials (IAEA-C1, C4, C5, C6, C7, C9 and NIST-SRM4990C) at JAEA-AMS-TONO. Graphite samples was prepared by the AGE3 system and radiocarbon concentration of these standards was measured by AMS. The results were agreement with the consensus values. Background values were 0.15$$pm$$0.01 pMC (IAEA-C1) using the AGE3 system. Therefore, we concluded that the system can be adapted for radiocarbon dating of geological samples.

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

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

no abstracts in English

Journal Articles

Present status of the accelerator facility at the JAEA-AMS-TONO; 2016

Fujita, Natsuko; Miyake, Masayasu; Watanabe, Takahiro; Kokubu, Yoko; Ishimaru, Tsuneari; Matsubara, Akihiro*; Nishio, Tomohiro*; Kato, Motohisa*; Isozaki, Nobuhiro*; Torazawa, Hitoshi*; et al.

JAEA-Conf 2018-013, p.96 - 99, 2019/02

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

JAEA Reports

Gas-strip methods of dissolved inorganic carbon in groundwater for radiocarbon analysis

Kato, Toshihiro; Iwatsuki, Teruki; Nishio, Tomohiro*

JAEA-Technology 2017-009, 30 Pages, 2017/06

JAEA-Technology-2017-009.pdf:2.6MB

Groundwater age is an important information to infer the groundwater flow. The radiocarbon ($$^{14}$$C) dating of the groundwater is primary method for the evaluation of groundwater flow. The carbon in the groundwater generally exist as a dissolved inorganic carbon (DIC). Though DIC in groundwater samples is usually collected by chemical precipitation method, the method requires lots of preparation to sample the carbon. Furthermore there are problems with the reproducibility on precipitation and measurement value. This study newly examined the application of gas-strip method to collect DIC in groundwater sample by using JAEA-made gas-strip system. The performance of the CO$$_{2}$$ gas-stripping from groundwater and the influence of sulfide are investigated. Based on these results, the operation procedures of gas-strip system and preparation method for the groundwater samples were summarized in this report.

Journal Articles

Present status of the JAEA-AMS-TONO; 2016

Fujita, Natsuko; Miyake, Masayasu; Watanabe, Takahiro; Kokubu, Yoko; Ishimaru, Tsuneari; Matsubara, Akihiro*; Isozaki, Nobuhiro*; Nishio, Tomohiro*; Kato, Motohisa*; Torazawa, Hitoshi*; et al.

Dai-19-Kai AMS Shimpojiumu, 2016-Nendo "Jumoku Nenrin" Kenkyukai Kyodo Kaisai Shimpojiumu Hokokushu, p.68 - 71, 2017/06

no abstracts in English

Journal Articles

Present status of the tandem accelerator at the JAEA-AMS-TONO; 2015

Fujita, Natsuko; Matsubara, Akihiro*; Watanabe, Takahiro; Kokubu, Yoko; Umeda, Koji*; Ishimaru, Tsuneari; Nishizawa, Akimitsu*; Miyake, Masayasu; Owaki, Yoshio*; Nishio, Tomohiro*; et al.

Dai-29-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.39 - 42, 2017/03

no abstracts in English

Journal Articles

Present status of the JAEA-AMS-TONO; 2015

Fujita, Natsuko; Matsubara, Akihiro; Watanabe, Takahiro; Kokubu, Yoko; Umeda, Koji; Nishizawa, Akimitsu*; Miyake, Masayasu*; Owaki, Yoshio*; Nishio, Tomohiro*; Kato, Motohisa*

Dai-18-Kai AMS Shimpojiumu Hokokushu, p.85 - 90, 2016/12

no abstracts in English

Journal Articles

Progress on multi-nuclide AMS of JAEA-AMS-TONO

Kokubu, Yoko; Matsubara, Akihiro; Miyake, Masayasu*; Nishizawa, Akimitsu*; Owaki, Yoshio*; Nishio, Tomohiro*; Sanada, Katsuki*; Hanaki, Tatsumi

Nuclear Instruments and Methods in Physics Research B, 361, p.48 - 53, 2015/10

 Times Cited Count:13 Percentile:81.43(Instruments & Instrumentation)

The JAEA-AMS-TONO facility was established in 1997 at the Tono Geoscience Center, Japan Atomic Energy Agency. Our AMS system has been made available for $$^{14}$$C- and $$^{10}$$Be-AMS. At present, the development of $$^{26}$$Al-AMS has been conducted to enhance the capability for multi-nuclide AMS. In this presentation, we report the progress on multi nuclide AMS in addition to the status of our facility.

Journal Articles

Present status of the JAEA-AMS-TONO; FY2013

Matsubara, Akihiro; Fujita, Natsuko; Nishizawa, Akimitsu*; Miyake, Masayasu*; Nishio, Tomohiro*; Owaki, Yoshio*; Sanada, Katsuki*; Kokubu, Yoko; Ishimaru, Tsuneari

Dai-27-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.47 - 51, 2015/03

Steady progress has been made in the development of a multi-nuclide AMS system for measurement of rare radionuclides ($$^{10}$$Be, $$^{14}$$C, and $$^{26}$$Al) to apply geochronological dating methods. In this article we will report the current status of the JAEA-AMS-TONO.

Journal Articles

Radiocarbon dating of seeds and a wood excavateed at Emon site

Kokubu, Yoko; Matsubara, Akihiro; Ishimaru, Tsuneari; Miyake, Masayasu*; Nishizawa, Akimitsu*; Owaki, Yoshio*; Nishio, Tomohiro*

Heisei-24-Nendo Tokishi Shinai Iseki Hakkutsu Chosa Hokokusho, p.28 - 30, 2014/03

Radiocarbon dating using accelerator mass spectrometry (AMS) was performed on Gramineae spp. seeds and a wood trunk collected from layers of IVb and Vb at the trench 1 of Emon site. After counting of number of tree rings of the trunk, 5 rings containing the outermost layer and the innermost one were cut to obtain wiggle-matched calibrated ages. In JAEA-AMS-TONO, graphite were made from the seeds and the rings and then their carbon isotope ratios were measured by AMS to obtain radiocarbon date. Calendar ages were calculated from the radiocarbon dates. Calendar ages of two seeds collected from the IVb layer were ranged between century of 15 and 17. That of the outermost layer of the trunk was about 1300 calAD, which was older than those of the seeds. On the other hand, those of the seeds collected from the Vb layer were 14 century.

Journal Articles

Current status of the AMS facility at the Tono Geoscience Center of the Japan Atomic Energy Agency

Kokubu, Yoko; Nishizawa, Akimitsu*; Suzuki, Mototaka*; Owaki, Yoshio*; Nishio, Tomohiro*; Matsubara, Akihiro; Saito, Tatsuo; Ishimaru, Tsuneari; Umeda, Koji; Hanaki, Tatsumi

Nuclear Instruments and Methods in Physics Research B, 294, p.43 - 45, 2013/01

 Times Cited Count:3 Percentile:29.69(Instruments & Instrumentation)

The Tono Geoscience center of JAEA installed the JAEA-AMS-TONO system at 1997. Since 1998, the system has routinely used for $$^{14}$$C-AMS. Recently, about 800 samples/y have been measured mainly for studies of neotectonics and hydrogeology in relation to research of geosphere stability for long-term Isolation of high-level radioactive waste. Under the common-use facility program, the system has also been used by researchers of universities and other institutes. In addition, $$^{10}$$Be-AMS has been developed for geochronological study. A gas ionisation detector was exchanged. As the detector has a gas absorber cell which has larger volume than the previous one, it is possible to remove $$^{10}$$B efficiently. Test measurement by using several standard samples supplied from University of California, Berkeley was performed. Ratios of $$^{10}$$Be/$$^{9}$$Be were comparable to the certified values, indicating that our system has sufficient ability to be useful to $$^{10}$$Be-AMS.

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