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Journal Articles

Temporal variability of $$^{137}$$Cs concentrations in coastal sediments off Fukushima

Suzuki, Shotaro*; Amano, Yosuke*; Enomoto, Masahiro*; Matsumoto, Akira*; Morioka, Yoshiaki*; Sakuma, Kazuyuki; Tsuruta, Tadahiko; Kaeriyama, Hideki*; Miura, Hikaru*; Tsumune, Daisuke*; et al.

Science of the Total Environment, 831, p.154670_1 - 154670_15, 2022/07

 Times Cited Count:2 Percentile:32.35(Environmental Sciences)

Journal Articles

Study of charged particle activation analysis, 2; Determination of boron concentration in human blood samples

Ikebe, Yurie*; Oshima, Masumi*; Bamba, Shigeru*; Asai, Masato; Tsukada, Kazuaki; Sato, Tetsuya; Toyoshima, Atsushi*; Bi, C.*; Seto, Hirofumi*; Amano, Hikaru*; et al.

Applied Radiation and Isotopes, 164, p.109106_1 - 109106_7, 2020/10

 Times Cited Count:2 Percentile:24.76(Chemistry, Inorganic & Nuclear)

Boron Neutron Capture Therapy (BNCT) is a radiotherapy for the treatment of intractable cancer. In BNCT precise determination of $$^{10}$$B concentration in whole blood sample before neutron irradiation is crucial for control of the neutron irradiation time and the neutron dosimetry. We have applied the Charged Particle Activation Analysis (CPAA) to non-destructive and accurate determination of $$^{10}$$B concentration in whole blood sample. The experiment was performed at JAEA Tandem Accelerator using an 8 MeV proton beam. The 478 keV $$gamma$$ ray of $$^{7}$$Be produced in the $$^{10}$$B(p,$$alpha$$)$$^{7}$$Be reaction was used to quantify the $$^{10}$$B, and $$gamma$$ rays of $$^{56}$$Co originating from the reaction with Fe in blood was used to normalize the $$gamma$$-ray intensity. The results demonstrated that the present CPAA method can be applied to the determination of the $$^{10}$$B concentration in the blood sample.

Journal Articles

Vertical distributions of global fallout $$^{137}$$Cs and $$^{14}$$C in a Japanese forest soil profile and their implications for the fate and migration processes of Fukushima-derived $$^{137}$$Cs

Koarashi, Jun; Atarashi-Andoh, Mariko; Amano, Hikaru*; Matsunaga, Takeshi

Journal of Radioanalytical and Nuclear Chemistry, 311(1), p.473 - 481, 2017/01

 Times Cited Count:17 Percentile:85.51(Chemistry, Analytical)

Vertical distributions of global fallout $$^{137}$$Cs and $$^{14}$$C were investigated in a Japanese forest soil in 2001. Even 38 years after the fallout, $$^{137}$$Cs was still observed mostly in the uppermost 5 cm. A preferential accumulation of $$^{137}$$Cs was found in a 1-cm-thick transition layer between organic-rich A and underlying B horizons. This unique observation indicated that $$^{137}$$Cs migrated through the A horizon at a rate of 0.20% y$$^{-1}$$ and the transition layer acted as a barrier for $$^{137}$$Cs migration to deeper layers. The vertical distributions of $$^{137}$$Cs and $$^{14}$$C were significantly correlated, suggesting a coupled downward migration of $$^{137}$$Cs and organic matter on a time scale of decades, along the same physical pathways.

Journal Articles

Evaluation of neutron dose released in the environment by activation of gold

Kushita, Kohei; Atarashi-Andoh, Mariko; Amano, Hikaru*

Bunseki Kagaku, 63(11), p.867 - 871, 2014/11

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

We report here the study of activated gold for the estimation of neutron dose in the environment in the case of JCO criticality accident happened in Tokai, Japan, in 1999. We collected and analyzed 16 gold samples, such as ring, coin or necklace stored at residents houses in the range from 168 to 568 m from the accident place of JCO. They gave activities from 91.9 to 0.322 Bq/g-Au as standardized values at 06:15, Oct. 1, 1999, when the criticality reaction had ceased after 20 hours of continuation. The induced radioactivity of gold samples showed a good correlation as a power function of distance. The induced radioactivity of gold is discussed with reference data to estimate dose equivalent in the environment around JCO. This paper gives an example showing the usefulness of gold in the field of nuclear and radiation studies and applications.

Journal Articles

Behavior of environmental tritium at NIFS Toki Site of Japan

Sugihara, Shinji*; Tanaka, Masahiro*; Tamari, Toshiya*; Shimada, Jun*; Takahashi, Tomoyuki*; Momoshima, Noriyuki*; Fukutani, Satoshi*; Atarashi-Andoh, Mariko; Sakuma, Yoichi*; Yokoyama, Sumi*; et al.

Fusion Science and Technology, 60(4), p.1300 - 1303, 2011/11

 Times Cited Count:2 Percentile:18.37(Nuclear Science & Technology)

The purpose of this study is to develop the technique to evaluate the environmental tritium behavior of the nuclear facility origin. Tritium concentrations of river water, precipitation and ground water around the NIFS site were determined by low background liquid scintillation measurement system combined with the electrolysis using solid polymer electrolyte. The electric conductivity and flow rate of the river and isotopic ratio of oxygen and hydrogen of water samples were also measured. The tritium concentrations in precipitation showed the seasonal variation and the range were 0.09-0.78 Bq/L. The tritium concentrations of river water and ground water were almost constant, 0.34 and 0.24 Bq/L respectively. The simple dynamic model for the site around the NIFS facilities was developed using measured data, and the behavior of tritium was simulated.

Journal Articles

The Vertical profiles of iodine-129 in the Pacific Ocean and the Japan Sea before the routine operation of new nuclear fuel reprocessing plant

Suzuki, Takashi; Minakawa, Masayuki*; Amano, Hikaru; Togawa, Orihiko

Nuclear Instruments and Methods in Physics Research B, 268, p.1229 - 1231, 2010/04

 Times Cited Count:25 Percentile:84.31(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Preliminary result of dissolved organic radiocarbon in the western North Pacific Ocean

Tanaka, Takayuki; Otosaka, Shigeyoshi; Wakita, Masahide*; Amano, Hikaru*; Togawa, Orihiko

Nuclear Instruments and Methods in Physics Research B, 268(7-8), p.1219 - 1221, 2010/04

 Times Cited Count:9 Percentile:54.31(Instruments & Instrumentation)

Dissolved organic carbon (DOC) in seawater is one of the largest reservoirs of organic matter on the earth's surface, holding approximately as much carbon as available in atmospheric CO$$_{2}$$. As a result of the huge carbon reservoir, the role and dynamics of DOC have become of greater interest in the global carbon cycle. It has been suggested that dissolved organic radiocarbon ($$Delta$$$$^{14}$$C-DOC) in seawater is a powerful tool to understand the dynamics of DOC and its researches have been carried out using AMS. However, there are very few data in the world oceans because of the difficulties of the measurement technique. Although it has been represented that the western North Pacific plays an important role in the carbon cycle from the viewpoint of a terminal of the deep water circulation in the world oceans and a high biological activity, $$Delta$$$$^{14}$$C-DOC has not been measured yet. In this study, we obtained its vertical profile in the western North Pacific for the first time.

Journal Articles

$$^{14}$$C concentration in tree rings of beech trees living near CO$$_{2}$$ vents in the Hakkoda Cardera, Aomori, Japan

Horiuchi, Kazuho*; Chiba, Takuji*; Hoshino, Yasuharu*; Oyama, Motonari*; Tanaka, Takayuki; Amano, Hikaru*

JAEA-Conf 2010-001, p.71 - 74, 2010/03

We investigated how volcanic CO$$_{2}$$ emission affects the $$^{14}$$C concentrations in tree rings of beech trees in the Hakkoda Caldera in Aomori, which is one of high emission regions of volcanic CO$$_{2}$$ in the world. There was a tendency that the obtained $$^{14}$$C concentrations were, surprisingly, quite near to the values of the concurrent atmospheric CO$$_{2}$$ and decreased from 1991 to 2001. The $$^{14}$$C concentrations in caldera are lower than those of the control samples taken from a beech living outside of the caldera. We revealed the possibility that we can solve the local dynamics of fossil CO$$_{2}$$ emission using $$^{14}$$C in tree rings. However, the maximum difference of $$^{14}$$C between inside and outside of the caldera was 14 permil. This result showed that the volcanic CO$$_{2}$$ mixed with atmospheric CO$$_{2}$$ by 4.4 ppm or less. As the trunk absorbing CO$$_{2}$$ exist in height that is several meters higher than the volcanic CO$$_{2}$$ vents, the low mixing may occur.

Journal Articles

Development of an extraction method for the determination of dissolved organic radiocarbon in seawater by accelerator mass spectrometry

Tanaka, Takayuki; Otosaka, Shigeyoshi; Amano, Hikaru; Togawa, Orihiko

Journal of Nuclear Science and Technology, 46(3), p.289 - 294, 2009/03

 Times Cited Count:2 Percentile:17.74(Nuclear Science & Technology)

We developed an extraction system of carbon from dissolved organic carbon (DOC) to achieve its accurate and precision $$^{14}$$C measurement by AMS. The system was devised for reducing the blank carbon by decreasing the contamination of dead carbon mainly induced from oil products and CO$$_{2}$$ in air, and for extracting it from large volume seawater. The developed system gained lower blank than the previous studies to be less than 1% of sample size. It was demonstrated that the $$^{14}$$C value extracted from organic material by the system of lower blank was agreed with that by the conventional combusted method and the precision was very low value of $$pm$$5‰. Results indicated that the system achieved the high accuracy and precision for $$^{14}$$C. We tied to measure DO$$^{14}$$C in large volume seawater and confirmed the great extraction and good precision to be $$pm$$8‰. Results revealed that the system attained the supreme accuracy and precision for DO$$^{14}$$C in large volume seawater.

Journal Articles

Deep sea circulation of particulate organic carbon in the Japan Sea

Otosaka, Shigeyoshi; Tanaka, Takayuki; Togawa, Orihiko; Amano, Hikaru; Karasev, E. V.*; Minakawa, Masayuki*; Noriki, Shinichiro*

Journal of Oceanography, 64(6), p.911 - 923, 2008/12

 Times Cited Count:22 Percentile:47.15(Oceanography)

Transport processes of particulate organic carbon (POC) were inferred from sediment trap experiments in the three regions of the Japan Sea (western and eastern Japan Basin and Yamato Basin) and radiocarbon measurement. Annual mean $$^{14}$$C/$$^{12}$$C isotopic ratio decreased with depth and the vertical changes in the isotopic signature were considered to indicate mixing of two fractions; labile POC produced in the surface and refractory POC. From seasonal variations of POC flux of the two fractions, transport processes of POC in the Japan Sea were summarized as follows: (1) In the Japan Basin, both labile and refractory POC were supplied in spring and a reservoir of refractory POC was formed, and (2) in the Yamato Basin, larger amount of refractory POC were carried the interior and accumulated rapidly.

Journal Articles

Measurement of iodine-129 in seawater samples collected from the Japan Sea area using accelerator mass spectrometry; Contribution of nuclear fuel reprocessing plants

Suzuki, Takashi; Kabuto, Shoji; Amano, Hikaru; Togawa, Orihiko

Quaternary Geochronology, 3(3), p.268 - 275, 2008/08

 Times Cited Count:26 Percentile:54.23(Geography, Physical)

no abstracts in English

Journal Articles

Iodine-129 measurements in soil samples from Dolon village near the Semipalatinsk Nuclear Test Site

Endo, Satoru*; Tomita, Jumpei*; Tanaka, Kenichi*; Yamamoto, Masayoshi*; Fukutani, Satoshi*; Imanaka, Tetsuji*; Sakaguchi, Aya*; Amano, Hikaru; Kawamura, Hidehisa*; Kawamura, Hisao*; et al.

Radiation and Environmental Biophysics, 47(3), p.359 - 365, 2008/07

 Times Cited Count:5 Percentile:21.13(Biology)

Dolon village located about 60 km from the border of the Semipalatinsk Nuclear Test Site is known to be heavily contaminated by the first USSR atomic bomb test in August 1949. Soil samples around Dolon were taken in October 2005 in an attempt to evaluate internal thyroid dose arising from incorporation of radioiodine isotopes (mainly $$^{131}$$I). Iodine-129 in soil was measured by using the technique of Accelerator Mass Spectrometry. From the relationship between $$^{129}$$I and $$^{137}$$Cs (corrected for background and decay from 1949 to 2005) accumulated levels, the background level of $$^{129}$$I and the $$^{129}$$I/$$^{137}$$Cs ratio around Dolon were estimated to be (6.4 $$pm$$0.4) $$times$$ 10$$^{13}$$ atoms m$$^{-2}$$ and 0.25 $$pm$$0.16, respectively. This $$^{129}$$I/$$^{137}$$Cs ratio is almost similar to the fission yield ratio for $$^{239}$$Pu fast fission (0.24).

Journal Articles

Application accelerator mass spectrometer to environmental sciences and health physics

Amano, Hikaru

Hoshasen To Sangyo, (118), p.25 - 32, 2008/06

Accelerator Mass Spectrometer (AMS) is a quite useful tool to determine precisely ultra low level amounts of long lived radio nuclides. This method has mainly been applied not only to the field of archeology, but also to the field of environmental sciences and health physics. It is utilized as a tracer to analyze environmental issues, because it assures high sensitivity measurement in short time in addition to small amounts. In the field of nuclear and health physics, it opens the door to detect long lived radio nuclides which can not be determined in traditional radiometric methods. This review summarizes recent application of AMS to environmental sciences and health physics.

JAEA Reports

Proceedings of the 1st JAEA Tandetron AMS Utilization Workshop; November 14, 2007, Mutsu-shi Japan

Amano, Hikaru; Kabuto, Shoji

JAEA-Conf 2008-003, 90 Pages, 2008/04


Accelerator Mass Spectrometer (AMS) can determine ultra low level long-lived radioactive isotopes in high sensitivity and precision. Tandetron AMS had been adjusted for the measurement of $$^{14}$$C and $$^{129}$$I. The AMS has mainly been used for marine research around the Japan Sea. This AMS has adopted the open door policy for the general users from the spring of 2006. Recently varieties of research activities using this AMS have been in progress by many users. This biennial workshop aimed to not only exchange information on the AMS and its utilization but also continue stable operation of the AMS. First JAEA Tandetron AMS Utilization Workshop was held at Mutsu office, JAEA in November 14, 2007. In the workshop 76 participants attended. The topics of the conference concerned recent utilization status of AMS, data processing from the AMS, $$^{14}$$C and $$^{129}$$I measurement and their application, and so on. This proceeding includes 21 papers at the workshop.

Journal Articles

Biogeochemical cycle of particulate organic carbon in the Japan Sea and northwestern North Pacific

Otosaka, Shigeyoshi; Tanaka, Takayuki; Togawa, Orihiko; Amano, Hikaru

JAEA-Conf 2008-003, p.67 - 70, 2008/04

An apparent age of particulate organic matter (POM) in seawater that is estimated from isotopic ratio of radiocarbon is convenient indicator for verifying transport processes of POM in the ocean. However, it is suggested that isotopic ratio of radiocarbon also reflects mixing of old POM from the surrounding regions and seafloor as well as an age of the POM. In this study, we discuss the cause of the variation in apparent age of POM from radiocarbon measurements of various particulate materials obtained at the northeastern Japan Sea and the northwestern North Pacific.

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

Quality policy on radiocarbon measurement at the JAEA-Mutsu AMS

Otosaka, Shigeyoshi; Amano, Hikaru; Kabuto, Shoji; Kinoshita, Naoki; Tanaka, Takayuki

JAEA-Conf 2008-003, p.21 - 23, 2008/04

no abstracts in English

Journal Articles

Development of analysis system of dissolved organic radiocarbon and study on its circulation in sea water

Tanaka, Takayuki; Otosaka, Shigeyoshi; Amano, Hikaru; Togawa, Orihiko

JAEA-Conf 2008-003, p.71 - 74, 2008/04

no abstracts in English

Journal Articles

Measurement of $$^{129}$$I by JAEA AMS MUTSU and application to study of iodine migration

Suzuki, Takashi; Kabuto, Shoji; Kinoshita, Naoki; Amano, Hikaru; Togawa, Orihiko

JAEA-Conf 2008-003, p.24 - 27, 2008/04

no abstracts in English

Journal Articles

Operational status of the JAEA AMS-Mutsu tandem AMS

Kabuto, Shoji; Kinoshita, Naoki; Watanabe, Yukiya*; Baba, Masami*; Amano, Hikaru

JAEA-Conf 2008-003, p.13 - 16, 2008/04

no abstracts in English

170 (Records 1-20 displayed on this page)