EXCITATION-ENERGY DEPENDENCE OF THE TOTAL KINETIC-ENERGY RELEASE IN THE PU-241(HE-3,ALPHAF) REACTION

Total fission kinetic energies EK have been measured as a function of excitation energy in the Pu240 nucleus excited in the Pu241(He3,α) reaction. A small negative slope of dEKdE*A-0.05 is observed in the excitation energy region E*=5-9 MeV. This is substantially smaller than the slope of dEKdE*=-1.1 observed in the Pu240(α,α′f) reaction and slightly smaller than the slope of dEKdE*A-0.35 obtained from (d,pf) and neutron capture reactions. It is concluded that the primary reaction mechanism plays a decisive role for the total kinetic energy release at near barrier energies but that the angular momentum transfer is not the important parameter. The data are discussed in terms of a simple scission-point model, and in particular the effect of the Z=50, N=82 spherical doubly magic shell in the nascent fragments. NUCLEAR REACTIONS, FISSION Pu240; measured mass and total kinetic energy distributions as function of excitation energy. © 1979 The American Physical Society.