Pu Isotopes, ^<241>Am and ^<137>Cs in Soils from the Atomic Bombed Areas in Nagasaki and Hiroshima

概要

論文の詳細を見る
Plutonium Isotopes, ^<241>Am and ^<137>Cs in soil samples collected from Nagasaki and Hiroshima were measured to evaluate the contribution of residual radioactivity derived from the atomic bombs dropped in 1945. In the soils from Nishiyama area of Nagasaki City, activity ratios different from those of global fall-out were found for the ^<238>Pu/^<239,240>Pu (0.05-0.06), ^<239,240>Pu/^<131>Cs (0.2-0.3), ^<241>Am/^<239,240>Pu (0.04-0.05) and ^<240>Pu/^<239>Pu (0.08-0.13), activity ratios indicating that a fair amount of plutonium derived from the atomic bomb had accumulated in this area. On the other hand, in the soils from the "Black-rain" area of Hiroshima, no significant difference from the global fallout was found for the activity ratios among the Pu isotopes, ^<241>Am and ^<137>Cs except for the soils collected at 10 km and 12 km in the NNW direction from the epicenter, where a factor 2 to 3 lower ^<241>Am/^<239,240>Pu activity ratio was observed.
日本放射線影響学会の論文