JOPSS - Search Results

Journal Articles

Depositional processes of circular abandoned channels around the middle parts of the Kumano River, Southwest Japan

Nakanishi, Toshimichi*; Komatsu, Tetsuya; Ogata, Manabu; Kawamura, Makoto; Yasue, Kenichi*

Gekkan Chikyu "Kiso deta Kara Kangaeru Dai Yonkigaku No Shintenkai-I" Gogai No.71, p.148 - 155, 2022/02

The formation process of terrace topography was investigated by observing and analyzing boring core samples collected in the middle reaches of the Kumano River. It was assumed that the older terrace topography was distributed higher than the current riverbed surface. However, since tributary debris flow deposits may be thickly distributed beneath the old gyre river valley, care must be taken when using the surface of the ground as an index of uplift and erosion.

Journal Articles

Measurement time and result of apatite FT density using FT automatic measuring device

Shimada, Koji; Sueoka, Shigeru

Fisshion, Torakku Nyusureta, (33), p.19 - 21, 2020/10

no abstracts in English

Journal Articles

Dating of geological samples

Kokubu, Yoko

ISEE Newsletter, 9, P. 4, 2020/01

http://www.isee.nagoya-u.ac.jp/publication.html

no abstracts in English

Journal Articles

U-Pb dating of calcium carbonate using LA-ICP-MS

Yokoyama, Tatsunori

Isotope News, (764), p.11 - 14, 2019/08

https://www.jrias.or.jp/books/cat3/2019/764.html

no abstracts in English

Journal Articles

Degassing behavior of noble gases from groundwater during groundwater sampling

Nakata, Kotaro*; Hasegawa, Takuma*; Solomon, D. K.*; Miyakawa, Kazuya; Tomioka, Yuichi*; Ota, Tomoko*; Matsumoto, Takuya*; Hama, Katsuhiro; Iwatsuki, Teruki; Ono, Masahiko*; et al.

Applied Geochemistry, 104, p.60 - 70, 2019/05

https://doi.org/10.1016/j.apgeochem.2019.03.007

Times Cited Count：9 Percentile：38.79(Geochemistry & Geophysics)

no abstracts in English

Journal Articles

The 20th anniversary of JAEA-AMS-TONO

Ishimaru, Tsuneari

JAEA-Conf 2018-013, p.13 - 16, 2019/02

https://doi.org/10.11484/jaea-conf-2018-003

In the Tono Geoscience Center, JAEA-AMS-TONO was introduced in March 1997 and it will be the 20th year in this year. After introduction, we maintained the carbon-14 measurement first and we were able to steadily accumulate results.

Journal Articles

Uranium age-dating using in-situ isotope ratios by thermal ionization mass spectrometry for nuclear forensics

Okubo, Ayako; Shinohara, Nobuo; Magara, Masaaki

Journal of Radioanalytical and Nuclear Chemistry, 314(1), p.231 - 234, 2017/10

https://doi.org/10.1007/s10967-017-5379-7

Times Cited Count：2 Percentile：19.65(Chemistry, Analytical)

The model date of two enriched uranium materials were determined using a new method for nuclear forensics investigation. In this method, the $^{230}$ Th/ $^{234}$ U ratio was calculated without spike addition from measured ratios of $^{230}$ Th/ $^{234}$ Th and $^{234}$ U/ $^{238}$ U, and calculated $^{234}$ Th/ $^{238}$ U ratio in secular equilibrium. The obtained model date for the low-enriched uranium material was agreed with the known production date within uncertainty. For the highly enriched uranium material, slightly younger model date than the known production date was obtained. The $^{234}$ U interference on $^{234}$ Th counting in thermal ionization mass spectrometry measurement was suspected as a potential cause.

Journal Articles

$^{14}$ C ages and calendar years of Japanese swords measured with accelerator mass spectrometry

Nagata, Kazahiro*; Matsubara, Akihiro*; Kokubu, Yoko; Nakamura, Toshio*

Tetsu To Hagane, 102(12), p.736 - 741, 2016/12

https://doi.org/10.2355/tetsutohagane.TETSU-2016-036

Times Cited Count：2 Percentile：12.27(Metallurgy & Metallurgical Engineering)

Steel of Japanese swords has been produced with Tatara process from iron sand and charcoal. Carbon dissolved in steel was absorbed from wooden charcoal fuel at the production of the steel. From the decay of $^{14}$ C activity in the steel, the $^{14}$ C age of Japanese sword can be determined. The $^{14}$ C ages of 4 Japanese swords were calibrated to a few calendar years. There are several generations of the same names of sword masters. The year of production of each sword was determined from the calendar year and the sword master's name cut in the grip of his sword after taking the age of charcoal into account. The oldest calendar year with high probability agreed with the age of sword master.

Journal Articles

Cross-checking groundwater age by $^{4}$ He and $^{14}$ C dating in a granite, Tono area, central Japan

Hasegawa, Takuma*; Nakata, Kotaro*; Tomioka, Yuichi*; Goto, Kazuyuki*; Kashiwaya, Koki*; Hama, Katsuhiro; Iwatsuki, Teruki; Kunimaru, Takanori*; Takeda, Masaki

Geochimica et Cosmochimica Acta, 192, p.166 - 185, 2016/11

https://doi.org/10.1016/j.gca.2016.07.013

Times Cited Count：10 Percentile：38.79(Geochemistry & Geophysics)

Groundwater dating was performed simultaneously by the $^{4}$ He and $^{14}$ C methods in granite of the Tono area in central Japan. Groundwater was sampled at 30 packed-off sections of six 1000-m boreholes. $^{4}$ He concentrations increased and $^{14}$ C concentrations decreased along a groundwater flow path on a topographic gradient. $^{4}$ He ages were calculated by using the in situ $^{4}$ He production rate derived from the porosity, density, and U and Th content of the rock, neglecting external flux. The linear relation between the $^{4}$ He ages and the noncorrected $^{14}$ C ages, except in the discharge area. Simultaneous measurements make it feasible to estimate the accumulation rate of $^{4}$ He and initial dilution of $^{14}$ C, which cannot be done with a single method. Cross-checking groundwater dating has the potential to provide more reliable groundwater ages.

Journal Articles

Round-robin $^{230}$ Th- $^{234}$ U age dating of bulk uranium for nuclear forensics

Gaffney, A.*; Hubert, A.*; Kinman, W. S.*; Magara, Masaaki; Okubo, Ayako; Pointurier, F.*; Schorzman, K. C.*; Steiner, R. E.*; Williams, R. W.*

Journal of Radioanalytical and Nuclear Chemistry, 307(3), p.2055 - 2060, 2016/03

https://doi.org/10.1007/s10967-015-4334-8

Times Cited Count：22 Percentile：89.8(Chemistry, Analytical)

In and inter-laboratory measurement comparison study, four laboratories (LLNL, LANL, CEA, JAEA) determined $^{230}$ Th- $^{234}$ U model ages of uranium certified reference material NBL U050 using isotope dilution mass spectrometry. The model dates determined by the participating laboratories range from 9 March 1956 to 19 October 1957, and are indistinguishable given the associated measurement uncertainties. These model ages are concordant with to slightly older than the known production age of NBL U050, indicating unsufficient purification of U050.

Journal Articles

Accurate purification age determination of individual uranium-plutonium mixed particles

Miyamoto, Yutaka; Suzuki, Daisuke; Esaka, Fumitaka; Magara, Masaaki

Analytical and Bioanalytical Chemistry, 407(23), p.7165 - 7173, 2015/09

https://doi.org/10.1007/s00216-015-8880-2

Times Cited Count：8 Percentile：31.37(Biochemical Research Methods)

Age of individual uranium-plutonium mixed particles with various U/Pu atomic ratios were determined by inductively-coupled plasma mass spectrometry. Micron-sized particles were prepared from U and Pu certified reference materials. The Pu reference was stored for 4-6 years since the last purification. The Pu purification age was obtained from the $^{241}$ Am/ $^{241}$ Pu ratio which was calculated from the product of three measured ratios of Pu and Am isotopes in the eluted fractions. Am, U and Pu in a sample solution were sequentially separated a small anion-exchange column. The $^{241}$ Am/ $^{241}$ Pu ratio was accurately determined by spiking pure $^{243}$ Am to the sample solution. The determined age of particles with various U/Pu ratios was in good agreement with the expected age with high accuracy and high precision.