Energetics of Charged Particle-Induced Fission Reactions

Measurements with a semiconductor detector system and a two-dimensional analyzer have yielded information on the mass distributions and the details of the kinetic energy release from a series of charged particle-induced fission reactions. The fissioning compound nuclei range from thallium for which the mass distributions are symmetric, to plutonium for which the fission is predominantly asymmetric. In an intermediate region, the charged particle-induced fission of ${\mathrm{Ra}}^{226}$ yields comparable contributions of symmetric and asymmetric fission. All of the results are quantitatively consistent with a two-mode hypothesis for the fission process and indicate that within each mode the distance between the charge centers of the two fragments at the scission point is approximately the same for all mass divisions. The results show a lower total kinetic energy release from symmetric fission than from asymmetric fission, indicating that the distance between the charge centers at the scission point is about 10% greater for the symmetric mode than for the asymmetric mode.