Distribution of mass, kinetic energy, and neutron yield in the spontaneous fission ofFm254

The mass distribution for spontaneous fission of ${}_{}{}^{254}{}_{}{}^{}\mathrm{Fm}$ was determined for both pre- and post-neutron-emission fragments. The post-neutron-emission (final) mass distribution was deduced from radiochemical measurements of 24 mass yields. Starting with an assumed distribution of neutron yield versus fragment mass, the pre-neutron-emission (initial) mass distribution and neutron-yield distribution were derived from the kinetic-energy measurements of the fragments and the final-mass distribution by an interative method. These distributions together with distributions of fragment kinetic energy, total kinetic energy of both fragments, and average kinetic energy and average total kinetic energy as functions of fragment mass are presented. The results are discussed in terms of a scission-point model of fission.