Kinetic Energy Distributions in the Spontaneous Fission ofCm250andCf250

The kinetic energy distributions of coincident fragments from the spontaneous fission of ${}_{}{}^{250}{}_{}{}^{}\mathrm{Cm}$ and ${}_{}{}^{250}{}_{}{}^{}\mathrm{Cf}$ have been measured with silicon surface-barrier detectors. From these data, pre-neutron-emission kinetic energy and mass distributions have been calculated. The most probable value of the pre-neutron-emission total kinetic energy is 179.8 MeV for ${}_{}{}^{250}{}_{}{}^{}\mathrm{Cm}$, and 184.3 MeV for ${}_{}{}^{250}{}_{}{}^{}\mathrm{Cf}$. The resultant mass-yield curves are typical of asymmetric fission. The results are compared with measurements for other curium and californium isotopes.