降下及び落下塵の放射能について(第一報)

The analysis of the following data has shown that radioactlvity of the total fauout is approximately propotional to the amount of rainfall. And yet the activity per unit volume of precipitation decreases with increasing rainfall. This fact suggests that we must fairly consider the contribution of dry deposition. As a result from analysis of gamma-ray spectrum, six photopeaks have been observed evidently. It is estimated that these peaks are due to ^144Ce−^144Pr, ^103Ru, ^106Ru−^106Rh, ^95Zr−^95Nb and ^40K. The result of total beta-ray measurements was almost the same as that of gamma-rays.