抄録
Discrepancy between measured Eu-152 activity and theoretical calculation has long been discussed. Various ideas were examined to solve the problem on the bases that observed values are correct, however, agreeable answer has not been obtained. The Hiroshima and Nagasaki samples measured previously were re-measured by using extremely low background Ge detectors in Ogoya Underground Laboratory. As a results, Eu-152 could not be detected in the samples collected from more than 1000 m from hypo-center for Hiroshima and more than 600m for Nagasaki. New Eu-152 measurements were conducted for kg-size Hiroshima samples and compared with Cl-36 measurement by AMS method.Eu samples separated and enriched by the JCAC were measured at Ogoya during March to August in 2002 by large volume well type Ge. As a result, Eu-152 activities in 10 samples collected at 146m to 1400 m from hypocenter agreed well with theoretical calculation based on the DS86. [J Radiat Res 44:383 (2003)]
