量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果（学会誌発表論文、学会発表、研究開発報告書、特許等）を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum and Radiological Science and Technology.
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Abstract: Concentrations of neutron-induced BETA-ray emitters in the hair, blood, urine and bone of three workers severely exposed to neutrons in JOC criticality accident were measured with a low background BETA-ray spectrometer (Pico BETA) and liquid scintillation counter for the purpose of neutron dose estimation.32P is generated by the fast neutron of 2.5MeV and over in sulfur with (n, p) reaction. Since content of sulfur in hair is high as compared with the other human tissues, we tried to estimate fast neutron fluence to the body surface of the victims using concentrations of 32P and stable sulfur in their hair. The result shows that two workers, who were exposed to the higher neutron radiation than another worker, received higher doses of irradiation to the frontal side of their trunks than to the heads.For a more detailed mapping of neutron fluence in the body,the measurements of 32P and 45Ca induced by (n, GAMMA) reaction in bone were carried out. The results show that one worker (worker A) received a higher dose of neutrons at the frontal right side of the trunk, and that the dose decreased with the distance from the central part of the body. The other (worker B) seems to have gotten a higher dose of irradiation in the face, hands and waist.
High amount of 32P was detected in urine of the workers, and the concentration gradient among three workers showed a similar tendency to the estimated neutron dose from 24Na in blood. Therefore, radioactivity of 32P in urine could be used for estimating the neutron exposure dose. Moreover, the activity can be easily determined by scintillation counting, and urine is less invading bioassay sample that can be collected by non-medical stuffs.
生体試料中β放射性核種の測定
