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Abstract  

Low-energy photon spectrometry with -spectrometry was used to determine the environmental concentrations of low-level actinides and other nuclides, especially210Pb and210Po. The isotopic ratio of240Pu/239Pu was successfully determined by measuring Lx-ray/-ray counting ratio. A reliable method has been developed for the determination of extremely low-level237Np global fallout in environmental samples. The non-destructive determination by Ge-LEPS for natural210Pb in various samples (tobacco leaves, commercially available tobacco, etc.) was also carried out with the determination of210Po by -spectrometry using209Po as a yield tracer.

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Abstract  

For determining low level lithium concentrations in water, a neutron activation method based on the measurement of tritium radioactivity produced by6Li(n,)3H reaction has been developed. This method is specific and free from interference by other chemical elements. Using a low background liquid scintillation counter for tritium measurement, the detection limit is approximately 0.3 ppm during irradiation at a thermal neutron flux density of 1.1·107n·cm–2·s–1 for 6 hours by a small nuclear reactor and liquid scintillation counting for 2000 minutes

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Abstract  

In order to investigate the sedimentary behaviour of neptunium,237Np together with Pu isotopes and241Am have been measured for the sediment cores collected from Lake Mikata (freshwater) and from Lake Kugushi (brakish water) both belonging to the Mikata Five Lakes, and from Nyu Bay (sea water). In all sediment core samples237Np was detected, and its concentrations were far below those of239,240Pu and241Am measured for the same samples. Inventories of237Np in Lake Mikata, Lake Kugushi and Nyu Bay were estimated to be 0.53, 0.29 and 0.34 MBq/km2, respectively. The activity ratio of237Np/239,240Pu calculted from the inventories in each sediment core was 0.29% for Lake Mikata, 0.15% for Lake Kugushi and 0.10% for Nyu Bay. These values except for the value for Lake Mikata are two or three times lower than the value of 0.3–0.4% observed for surface soils of 0–20 cm depth, suggesting that Np is more soluble compared with Pu.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
S. Hisamatsu
,
T. Ohmura
,
Y. Takizawa
,
T. Katsumata
,
Y. Inoue
,
M. Itoh
,
K. Ueno
, and
M. Sakanoue

Abstract  

Tritium concentrations are reported for diet and human tissue samples collected in the Akita district of northern Japan. Sixteen separate food group samples and a total diet sample were collected for Akita City during April and May 1987. Six samples of heart and nine samples of kidney tissue were collected from 10 decreased individuals in Akita Prefecture from January to July 1986. Five serum and four blood samples were also obtained in Akita Prefecture from December 1985 to June 1986. Free water3H concentration as well as tissue-bound3H were determined separately. Specific activity ratios of tissue-bound3H to free water3H in the samples were almost between 1.0 and 2.0 and were similar to our previous results for food samples and other tissue samples. The specific activity ratio was also found to be lower than that reported in the U.S.A. and significantly lower than in Europe.

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