(1)Measurement of Eu-152 and Co-60

抄録

Residual activity data of 60Co and 152Eu were not enough to evaluate the dosimetry system DS86 in around 1987. Additional data of 152Eu, 60Co, 36Cl, 63Ni were accumulated both in Hiroshima and Nagasaki. The results of 152Eu in Hiroshima revealed that the measured data were 30-40% lower than the activation calculation based on the DS86 neutrons. The data beyond 1300 m ground range were not clarified because of detection limit o the gamma-ray measurement. The results of 60Co showed similar discrepancy as 152Eu. In the new dosimetry system DS02 (tentative name) , the coordinate of the hypocenter, the height of burst, the yield of the bomb were reevaluated. As a result, residual activity data and calculations show good agreement up to about 1300 m at Hiroshima and Nagasaki. [J Radiat Res 44:383 (2003)]