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Journal Articles

A Suitable procedure for preparing of water samples used in radiocarbon intercomparison

Takahashi, Hiroshi*; Minami, Masayo*; Aramaki, Takafumi*; Handa, Hiroko*; Kokubu, Yoko; Ito, Shigeru*; Kumamoto, Yuichiro*

Radiocarbon, 61(6), p.1879 - 1887, 2019/12

 Times Cited Count:1 Percentile:13.83(Geochemistry & Geophysics)

Water sample for interlaboratory comparison (here after "comparison water") must have inalterable $$^{14}$$C concentration during the comparison campaign and inter-batches homogeneity. In this study, the procedure for preparing of comparison water was discussed. We employed that comparison waters were artificially made by mixing chemical reagents, controlling $$^{14}$$C concentration and chemical composition. We could prepare six comparison waters, having 1, 14, 37, 56, 72 and 100 pMC, respectively. The stable carbon isotopic values and chemical compositions of some batches were measured to exanimate the inter- batches homogeneity. The $$^{14}$$C discrepancies among the batches were negligible for the inter-laboratory comparison. Finally, the results of trial comparison in Japan will be presented. Most of $$^{14}$$C results of CO$$_{2}$$ extracted by six laboratories showed good agreements each other.

Journal Articles

RICE-W (Radiocarbon Intercomparison on Chemical Experiments, Water series) program; An Examination of the precipitation method

Minami, Masayo*; Takahashi, Hiroshi*; Aramaki, Takafumi*; Kokubu, Yoko; Ito, Shigeru*; Nakamura, Toshio*

Nagoya Daigaku Kasokuki Shitsuryo Bunsekikei Gyoseki Hokokusho, 26, p.132 - 137, 2015/03

We have started a Radiocarbon Intercomparison on Chemical Experiments, Water series (RICE-W) program to examine whether carbon isotopic fractionation and carbon contamination occur or not on $$^{14}$$C analysis of dissolved inorganic carbon (DIC) in water by different sample preparation and storage methods. Eight water samples of four kinds (surface seawater, ground water, hot spring water, and sodium bicarbonate solution) have already analyzed by six AMS laboratories in Japan, and the results obtained are gradually being published. Here, we report the progress of RICE-W program briefly, and then give consideration to the result using the precipitation method, by which DIC is precipitated into SrCO$$_{3}$$ or BaCO$$_{3}$$, and then oxidized with H$$_{3}$$PO$$_{4}$$ to extract CO$$_{2}$$.

Journal Articles

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in $$p+p$$ and Au+Au collisions at $$sqrt{s_{NN}}$$ = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

 Times Cited Count:8 Percentile:52.71(Physics, Nuclear)

Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled $$p+p$$ collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to $$p+p$$ collisions.

Journal Articles

Iron distributions in the water column of the Japan Basin and Yamato Basin (Japan Sea)

Fujita, Satoshi*; Kuma, Kenshi*; Ishikawa, Satoko*; Nishimura, Shotaro*; Nakayama, Yuta*; Ushizaka, Satomi*; Isoda, Yutaka*; Otosaka, Shigeyoshi; Aramaki, Takafumi*

Journal of Geophysical Research, 115(C12), p.C12001_1 - C12001_12, 2010/12

 Times Cited Count:12 Percentile:36.67(Oceanography)

Vertical distributions of dissolved iron (D-Fe, less than 0.22 micrometer fraction), total iron (T-Fe, unfiltered), and chemical and biological components (e.g., nutrients) in seawater were determined at seven stations in the Japan Sea to understand the mechanisms that control iron behavior. Distributions of the D-Fe were characterized by surface depletion, mid-depth maxima, then slight decrease with depth in deep water and uniform concentration in bottom water because of biological uptake in the surface water and release from microbial decomposition of sinking organic matter in mid-depth water. The T-Fe concentrations in the deep-water column were variable with different T-Fe levels among stations and depths. We found a significant relationship of the exponential increase in the T-Fe concentrations with decreasing water transmittance, resulting from the iron supply into the deep and bottom waters due to the lateral transport of resuspended sediment from the continental slope.

Journal Articles

Spatial distribution of $$Delta$$$$^{14}$$C values of organic matter in surface sediments off Saru River in northern Japan, one year after a flood event in 2006

Nagao, Seiya*; Irino, Tomohisa*; Aramaki, Takafumi*; Ikehara, Ken*; Katayama, Hajime*; Otosaka, Shigeyoshi; Uchida, Masao*; Shibata, Yasuyuki*

Radiocarbon, 52(3), p.1068 - 1077, 2010/08

 Times Cited Count:0 Percentile:0.01(Geochemistry & Geophysics)

This study discusses the effects of flooding on the spatial distribution of organic matter on the shelf region of off the Saru River, southern part of Hokkaido, Japan, on the basis of the $$Delta$$$$^{14}$$C and $$delta$$$$^{13}$$C values. Surface sediments on the shelf were collected in August 2007, one year after the severe flood in 2006. Suspended particles and sediment of the Saru River were also collected in August 2007 and 2008. The $$Delta$$$$^{14}$$C values of organic matter in the shelf sediments ranged from -665 to -77 per mil. The silt and clay sediments had $$Delta$$$$^{14}$$C values of -240 to -77 per mil, but the sandy sediments ranged from -665 to -388 per mil. The $$Delta$$ values of particulate organic carbon in the Saru River are -292 to -247 per mil at normal flow conditions. These results indicate that surface soil with relatively older organic matter is deposited on the shelf region by the flooding event, and freshly-produced organic matter in sea surface is deposited after the flooding.

Journal Articles

Radiocarbon in the Japan Sea during the last 10 years

Aramaki, Takafumi*; Togawa, Orihiko; Otosaka, Shigeyoshi

JAEA-Conf 2010-001, p.39 - 43, 2010/03

no abstracts in English

JAEA Reports

Establishment of database for Japan Sea parameters on marine environment and radioactivity (JASPER), 2; Radiocarbon and oceanographic properties

Otosaka, Shigeyoshi; Suzuki, Takashi; Tanaka, Takayuki; Ito, Toshimichi; Kobayashi, Takuya; Kawamura, Hideyuki; Minakawa, Masayuki*; Aramaki, Takafumi*; Senju, Tomoharu*; Togawa, Orihiko

JAEA-Data/Code 2009-020, 27 Pages, 2010/02

JAEA-Data-Code-2009-020.pdf:2.45MB

The database for the Japan Sea parameters on marine environment and radionuclides (JASPER) has been established by the Japan Atomic Energy Agency as a product of the Japan Sea Expeditions. By the previous version of the database, data for representative anthropogenic radionuclides were opened to public. And now, data for radiocarbon and fundamental oceanographic properties (salinity, temperature, dissolved oxygen) including nutrients (silicate, phosphate, nitrate and nitrite) are released as the second volume of the database. In the second volume, 20,398 data records are stored including 2,695 data for temperature, 2,883 data for salinity, 2,109 data for dissolved oxygen, 11,051 data for the nutrients, and 1,660 data for radiocarbon. The database will be a strong tool for the continuous monitoring for contamination by anthropogenic radionuclides, studies on biogeochemical cycle, and development and validation of models for numerical simulations in the sea.

Journal Articles

Temporal and spatial variations of radiocarbon in Japan Sea Bottom Water

Kumamoto, Yuichiro*; Aramaki, Takafumi*; Watanabe, Shuichi*; Yoneda, Minoru*; Shibata, Yasuyuki*; Togawa, Orihiko; Morita, Masatoshi*; Shitashima, Kiminori*

Journal of Oceanography, 64(3), p.429 - 441, 2008/06

 Times Cited Count:10 Percentile:26.24(Oceanography)

In 1995 and 2000, radiocarbon ratio ($$Delta$$$$^{14}$$C) of total dissolved inorganic carbon was measured in the Japan Sea, a semi-closed marginal sea in the western North Pacific, where deep and bottom waters are formed in itself. Compiling them with historical radiocarbon data in the Japan Sea, temporal and spatial variations of the radiocarbon in the bottom water below 2000 m depth were elucidated. $$Delta$$$$^{14}$$C in the bottom waters in the western Japan and Yamato Basins increased by about 20 ‰ between 1977/79 and 1995 and did not changed between 1995 and 1999/2000, suggesting penetration of surface bomb-produced radiocarbon into the bottom waters due to bottom ventilation in the earlier period and stagnation of the bottom ventilation in the following period, respectively. In the eastern Japan Basin, the bottom $$Delta$$$$^{14}$$C increased by about 10 ‰ between 1977/79 and 2002, suggesting less ventilation of the bottom water in the basin. The temporal changes of the radiocarbon, tritium, and dissolved oxygen suggest sporadic occurrences of the bottom ventilation between 1979 and 1984 and its stagnation between 1984 and 2004 in the eastern Japan and Yamato Basins. The former is probably due to spreading of a newly ventilated bottom water in the western Japan Basin in the severe winter of 1976-1977 along the abyssal circulation in the Japan Sea. The latter does not conflict with temporal changes of bomb-produced $$^{137}$$Cs and chlorofluorocarbon-11 in the bottom water.

Journal Articles

Seawater movement in the Japan Sea inferred from $$^{14}$$C measurement in seawater

Otosaka, Shigeyoshi; Tanaka, Takayuki; Togawa, Orihiko; Amano, Hikaru; Aramaki, Takafumi*

JAEA-Conf 2008-003, p.63 - 66, 2008/04

Research Group for Environmental Science, JAEA has been carried out oceanographic observations in the Japan Sea. More than 3000 seawater samples for measurement of radiocarbon were collected during the observations. Radiocarbon in seawater samples was measured at AMS facility in JAEA Mutsu. In this presentation, circulation of water mass in the northern Japan Sea inferred from the radiocarbon measurement is discussed.

Journal Articles

Distribution of radiocarbon and bottom water circulation in the Japan Sea

Aramaki, Takafumi*; Togawa, Orihiko; Otosaka, Shigeyoshi; Suzuki, Takashi; Amano, Hikaru; Tanaka, Takayuki; Senju, Tomoharu*; Minakawa, Masayuki*

JAEA-Conf 2008-005, p.149 - 152, 2008/03

no abstracts in English

Journal Articles

Circulation in the northern Japan Sea studied chiefly with radiocarbon

Aramaki, Takafumi*; Senju, Tomoharu*; Togawa, Orihiko; Otosaka, Shigeyoshi; Suzuki, Takashi; Kitamura, Toshikatsu; Amano, Hikaru; Volkov, Y. N.*

Radiocarbon, 49(2), p.915 - 924, 2007/10

 Times Cited Count:8 Percentile:26.24(Geochemistry & Geophysics)

no abstracts in English

Journal Articles

Benthic front and the Yamato Basin Bottom Water in the Japan Sea

Senju, Tomoharu*; Isoda, Yutaka*; Aramaki, Takafumi*; Otosaka, Shigeyoshi; Fujio, Shinzo*; Yanagimoto, Daigo*; Suzuki, Takashi; Kuma, Kenshi*; Mori, Kosuke*

Journal of Oceanography, 61(6), p.1047 - 1058, 2005/12

 Times Cited Count:7 Percentile:16.33(Oceanography)

The detail structure of the Bottom Water in the Japan Sea was revealed by the hydrographic observations. The Yamato Basin Bottom Water (YBBW) exhibits higher temperature, lower dissolved oxygen, and higher nutrients concentrations than those in the Japan Basin Bottom Water (JBBW). Both Bottom Waters meet around the boundary region between the Yamato and the Japan Basins, and form a clear benthic front. It is inferred from the property distributions that the JBBW flowing into the Yamato Basin is trapped by the cyclonic circulation in the basin, and modified to the YBBW in the course of the circulation through the vertical diffusion, geothermal heating and oxygen consumption. The thermal balance of in the YYBW was examined using a box-model. The results show that the effect of geothermal heating has about 70 per-cent of magnitude to the vertical thermal diffusion and both terms cancel the advection term of the cold JBBW from the Japan Basin. The box-model also estimated the averaged residence time for the YBBW was 9.1 years.

Journal Articles

Anthropogenic radionuclides in seawater of the Japan Sea; The Results of recent observations and the temporal change of concentrations

Ito, Toshimichi; Aramaki, Takafumi*; Otosaka, Shigeyoshi; Suzuki, Takashi; Togawa, Orihiko; Kobayashi, Takuya; Kawamura, Hideyuki; Amano, Hikaru; Senju, Tomoharu*; Chaykovskaya, E. L.*; et al.

Journal of Nuclear Science and Technology, 42(1), p.90 - 100, 2005/01

 Times Cited Count:13 Percentile:68.06(Nuclear Science & Technology)

During 1996-2002, a wide-area research project on anthropogenic radionuclides was done in the Japanese and Russian EEZ of the Japan Sea to investigate their migration. As the results of expeditions in 2001 and 2002, (1) the concentrations and distributions of radionuclides are similar to the results of previous, (2) inventories of these radionuclides indicate accumulation in the Japan Sea seawater compared to the amounts supplied by global fallout, (3) $$^{90}$$Sr and $$^{137}$$Cs concentrations in intermediate layer show temporal variations, and 4) the variations may reflect the water mass movement in upper part of the Japan Sea.

Journal Articles

Radiocarbon in the water column of the Southwestern North Pacific Ocean; 24 years after GEOSECS

Povinec, P. P.*; Aramaki, Takafumi*; Burr, G. S.*; Jull, A. J. T.*; Liong Wee Kwong, L.*; Togawa, Orihiko

Radiocarbon, 46(2), p.583 - 594, 2004/09

 Times Cited Count:15 Percentile:33.12(Geochemistry & Geophysics)

no abstracts in English

Journal Articles

Performance of the new iodine-129 beamline at JAERI-AMS

Suzuki, Takashi; Aramaki, Takafumi; Kitamura, Toshikatsu; Togawa, Orihiko

Nuclear Instruments and Methods in Physics Research B, 223-224(1-4), p.87 - 91, 2004/08

 Times Cited Count:13 Percentile:66.18(Instruments & Instrumentation)

At the Japan Atomic Energy Research Institute, an Accelerator Mass Spectrometer which was installed in Mutsu establishment has two independent beam lines. We verified the precision, the accuracy and the detection limit at this AMS iodine line. Acceptance test for $$^{129}$$I measurement was carried out on two consecutive days and the $$^{129}$$I/$$^{127}$$I ratios obtained during these two days were (7.497$$pm$$0.119) $$times$$10 $$^{-11}$$ and (7.209$$pm$$0.050) $$times$$10 $$^{-11}$$ , respectively and the relative standard deviations from the $$^{129}$$I/$$^{127}$$I averages per sample were 1.6 % and 0.7 %, respectively. Seawater samples were collected in the western North Pacific and off Rokkasho, Japan before the operation of a nuclear fuel reprocessing plant. Seawater samples preparation for $$^{129}$$I -AMS measurement was performed by an extraction method. This paper was summarized the performance of this AMS iodine line and measurement results of $$^{129}$$I/$$^{127}$$I ratio in seawater samples.

Journal Articles

Distribution of radiocarbon in the Sea of Japan (prompt report)

Aramaki, Takafumi*; Togawa, Orihiko; Kitamura, Toshikatsu

Dai-16-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.170 - 172, 2004/02

no abstracts in English

Journal Articles

Performance of iodine line at JAERI-AMS

Suzuki, Takashi; Aramaki, Takafumi*; Kitamura, Toshikatsu; Togawa, Orihiko

Dai-16-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.162 - 165, 2004/02

no abstracts in English

Journal Articles

Benthic front between the Japan Basin and the Yamato Basin in the Japan Sea

Senju, Tomoharu*; Isoda, Yutaka*; Aramaki, Takafumi; Otosaka, Shigeyoshi; Suzuki, Takashi; Kuma, Kenshi*; Mori, Kosuke*

Proceedings of 12th PAMS/JECSS Workshop, p.3_4_1 - 3_4_4, 2003/11

Abyssal water mass distribution from the Yamato Basin to the Japan Basin in the Japan Sea was observed on the R/V Hakuho-Maru cruise, KH02-3 (October 14-19, 2002). The bottom layer in the Yamato Basin was occupied by the water of higher temperature and lower oxygen compared to that in the Japan Basin. As a result, a benthic front of potential temperature and dissolved oxygen was formed between the Yamato and Japan Basins. Dissolved oxygen and nutrients concentrations show that the bottom water in the Yamato Basin is older than that in the Japan Basin. This indicates the existence of the Yamato Basin Water, which is modified bottom water by the closed circulation in the Yamato Basin. The structure of the benthic front suggests an estuary-like circulation around the mouth of the Yamato Basin; outflow from the Yamato Basin lying on the inflow from the Japan Basin. The highest oxygen water was found on the slope of southern periphery of the Japan Basin. This is considered to be the bottom water from the west transported by the cyclonic circulation in the Japan Basin.

Journal Articles

CFC indicating renewal of the Japan Sea deep water in winter 2000-2001

Tsunogai, Shizuo*; Kawada, Kentaro*; Watanabe, Shuichi*; Aramaki, Takafumi

Journal of Oceanography, 59(5), p.685 - 693, 2003/10

 Times Cited Count:24 Percentile:46.36(Oceanography)

The water column distributions of CFC (chlorofluorocarbon) were determined twice in 2000 and 2001 in the northwestern Japan Sea. In 2000, the CFC-11 concentration decreased almost exponentially with depth from 6 pmol/kg at a few hundred m deep to 0.3 pmol/kg or less at the bottom of about 3400 m depth at 3 stations about 300 km off Vladivostok. In 2001, the CFC-11 concentration increased extremely up to 2 pmol/kg in the bottom water, while it did not increase at a station about 450 km away to the northeast. This is due to the renewal of the bottom water replaced by the surface water flowing down along the continental slope. The increase in the CFC-11 concentration was observed even in the whole water column above 3000 m depth. The increase in inventory is almost four times larger than that in the bottom water below 3000 m depth and equals about 1/6 of the total inventory found in 2000. The increase also means that 3 % of the deep water was replaced by the recent surface water or the turnover time of the deep water to be about 30 years, if the turnover occurs every year.

Journal Articles

Anthropogenic radionuclides in seawater of the Japan Sea; The Results of recent expeditions carried out in the Japanese and Russian EEZ

Ito, Toshimichi; Aramaki, Takafumi*; Otosaka, Shigeyoshi; Suzuki, Takashi; Togawa, Orihiko; Kobayashi, Takuya; Senju, Tomoharu*; Chaykovskaya, E. L.*; Lishavskaya, T. S.*; Karasev, E. V.*; et al.

Proceedings of International Symposium on Radioecology and Environmental Dosimetry, p.396 - 401, 2003/10

no abstracts in English

46 (Records 1-20 displayed on this page)