γ線スペクトル法による²³⁵Uと²³⁸Uの同位体比測定

抄録

It is well known that the ²³⁵U content in uranium can be determined by comparing γ-activities from ²³⁵U and those from ²³⁴Th and ^234m, ²³⁴Pa formed by the disintegration of ²³⁸U and in the radiochemical equilibria. Although this method looks convenient, it is not utilized widely, because about 8 months are necessary for attaining the equilibria after any chemical separation of uranium and thorium. In the present work, the above γ-spectrometric method was extended to uranium samples in which the equilibria are not yet attained. The proposed method determines 0.41% ²³⁵U at about 20 days after the purification of uranium from thorium. Values obtained agree well with those by the mass-spectrometry.