Mass Distribution and Kinetics ofU235Thermal-Neutron-Induced Three-Particle Fission

Abstract

The mass distribution, mass-energy correlations, and other kinetic parameters were obtained for U/sup 235/ thermalneutron-induced three-particle fission. The energies of the two heavy fragments and of the third light particle (usually a long-range alpha particle) were measured in coincidence using three- parameter correlation experiment. The mass distributions obtained for particles from binary and ternary fission indicate that the long-range alpha particles are emitted principally at the expense of nucleons in the light fragment for near- symmetric fission and at the expense of nucleons in the heavy fragment for more assymmetric fission Strong influence of the closed N = 82 and N = 50 shells is indicated. The mass distribution of the heavy fission products is essentially independent of longrange alpha-particle energy. The total fragment kinetic energy averaged over all mass ratios and over all alphaparticle energies is in slight disagreement with the previously reported value for ternary fission. (H.D.R.)