Dependence of fission-fragment total kinetic-energy and mass distributions on the excitation energy and angular-momentum distribution of the fissioning nuclide 210Po

The fission of 210Po, produced by three different nuclear reactions (209Bi + p, 206Pb + α and 198Pt + 12C), has been studied in detail in order to establish the dependence of various scission-point properties on the excitation energy and angular-momentum distribution of the fissioning nucleus. Excitation energies of 31, 44 and 57 MeV were chosen so as to give reasonable fission cross-sections, while avoiding a large contribution from second-chance fission. The experiments were conducted on a beam line of the Harwell Variable Energy Cyclotron. The mean-fragment total-kinetic-energy release was found to be dependent on the 210Po excitation energy and angular-momentum distribution. The variances of the total-kinetic energy and mass distributions were found to be a strongly dependent on excitation energy but not on angular momentum. The experimental results of this work were found to be in good agreement with the theoretical liquid-drop-model calculations of Nix and Swiatecki. (author)