Calculation of Fragment Excitation and Kinetic Energies in Nuclear Fission

We present a statistical model of fragment excitation in nuclear fission. The assumptions of the model are twofold. First we assume that the excitation of the single fragment is random, and can be described by a density distribution which is an exponential with a mean excitation energy of <E*>= a(cQ)². Here a is the level density parameter, and c is a constant which determines how much of the available Q-value is taken over to excitation. Secondly, the model implies that both fragments are excited almost independently during fission. We show that on this basis a full description of the energetics in the fission process emerges. The theory for spontaneous fission is easily extended to fission following nuclear reactions at higher energies. Calculation of mean values of single fragment excitation, total fragment excitation TXE, total kinetic energy TKE and single fragment kinetic energies are in quantitative agreement with experimental data.