Determination of the Charge and Mass Distribution in the Fission ofCf252

Abstract

A new technique is presented for determining mass and charge distribution in fission. This method is based on obtaining the independent yields of the even-even fission products from the measured intensities of $2^{+}\to 0^{+}$ ground-state band transitions deexciting the prompt-fission products. Transition intensities for members of ground-state bands in 36 even-even fission-product nuclei have been used to determine the centroids ($Z_p$) and widths (${\sigma }_Z$) of the charge distribution for eight chains of fission products with constant mass and also to determine the centroids ($Z_A$), widths (${\sigma }_A$), and yields ($Y_Z$) of the mass distribution for 12 chains of fission products with constant charge. The method has been applied to analyze the charge and mass distributions of ${}_{}{}^{252}{}_{}{}^{}\mathrm{Cf}$ spontaneous fission. The results when compared with the standard radiochemical and $K$ x-ray technique give satisfactory agreement. The discrepancies which exist are predominantly associated with regions influenced strongly by nuclear shells. Examples are given relating the observed ground-state band transition intensities with other observed fission variables such as kinetic energy release and neutron-evaporation systematics.