抄録
Isotopic abundances of xenon and krypton extracted from four kinds of uranium minerals were measured with a high sensitivity mass spectrometer. Experimental procedures of the extraction and the purification were described. The mass spectrometric analysis was carried out under static operations using xenon and krypton samples of 10-10-10-7 cc STP. In order to obtain the relative yields of xenon and krypton isotopes in U238spontan eous fission, the observed patterns were corrected for the neutron fission components and for the normal gas components. The spontaneous fission product patterns of xenon isotopes obtained from the pitchblendes(U: 35-70%)were in good agreement with that reported by Young and Thode. But the pattern obtained from the kobe-ite sample(U: 4.6%)differed to some extent from those. Conceivable reasons for this discrepancy were discussed.
