Historical trend of ^<137>Cs released from Nagasaki atomic bomb recorded in sediment core of Nishiyama reservoir at Nagasaki, Japan

概要

論文の詳細を見る
In the dated core sediment of Nishiyama reservoir at Nagasaki city, historical distribution of ^<137>Cs activity was determined. Sediment containing ^<137>Cs, which was deposited immediately after a detonation of Nagasaki atomic bomb, was identified in the core. Observed in the sediments were macroscopic charcoals, ^<239+240>Pu activity and ^<240>Pu/^<239>Pu isotopic ratio, and providing evidence for initial deposit of the fallout of the Nagasaki atomic bomb. This is the first entire depositional record of ^<137>Cs released from the Nagasaki atomic bomb together with these from atmospheric nuclear tests.