Po-210 distribution image and radioactivity determination in inner organ of fish with nuclear track detector CR-39

The distribution images of α-emission nuclides in the inner organ of dried sea fish such as sardine were obtained with nuclear track detector CR-39 by exposing for about 3 months. To obtain the radioactivity density in the inner organ from the pit density on the surface of CR-39, the detection efficiency of α-particle emitted in the organ was obtained by the calculation of energy loss of α-particles in the organ and in CR-39 using Bethe formula. The radioactivity densities were 1.3 Bq/cm3 and 85 Bq/cm3 for sardine and the liver of golden threadfin bream, respectively, and the energy absorption doses were 33 mGy/y and 2.2 Gy/y, respectively.