東海村における地表面大気中⁷Be濃度と降下量

抄録

Beryllium-7, cosmic ray produced radioactivity, its monthly average concentration in the lower atmosphere and monthly fallout rate were measured in Tokai, Japan. Then, the monthly variations were compared with those of fission products due to nuclear detonations in the atmosphere. The concentration of ⁷Be in the lower atmosphere ranged from 0.5×10^-1pCi/m³ to 2.5×10^-1pCi/m³ in Tokai between the observed period, 1975-1977. The fallout rate of ⁷Be vibrated widely, its range was from the detection limits to 1.2×10⁴pCi/m². The monthly variations were not always the same with variations of the fission products. Fallout rate of ⁷Be depended on the rain strongly.
The concentration of ⁷Be in the rain was measured, too. Then the range was from 9.2 pCi/l to 1.9×10²pCi/l between the observed period 1976. 9-1977. 2.