Distribution of Mass and Charge in the Fission ofCm245

The distribution of mass and charge in thermal-neutron-induced fission of ${}_{}{}^{245}{}_{}{}^{}\mathrm{Cm}$ has been investigated by radiochemical determination of the fission yields for 34 mass chains and 2 shielded nuclides (independent yields). ${}_{}{}^{245}{}_{}{}^{}\mathrm{Cm}$ is the heaviest nuclide fissionable by thermal neutrons to be investigated in this manner. The mass distribution is asymmetric; the heavy-mass group is centered at about the same position as in all previously investigated cases of low-energy fission, while the light-mass group is shifted to a higher mass number. The fission-yield data for ${}_{}{}^{245}{}_{}{}^{}\mathrm{Cm}$ indicate a value of 4±1 for $\overline{\nu }$, the average number of neutrons emitted per fission. The division of nuclear charge, as indicated by the independent yields of the shielded nuclides, adheres to a pattern characteristic of low-energy fission. A comparison of mass distributions in thermal-neutron-induced fission, reactor-neutron-induced fission, and spontaneous fission for several fissioning nuclei is given.