Fission partition a reflection of shell closures: Decay of 220,224U⁎ at eight excitation energies

Abstract

Decay modes of the compound systems formed in 86Kr + 134,138Ba → 220,224U⁎ reactions at eight excitation energies have been compared to explore the influence of shell closures and excitation energy. The mass distributions of the cross-sections have been calculated for the two compound systems by keeping their excitation energies the same. The production cross-section for the light particles, intermediate mass fragments, symmetric and asymmetric fission fragments, total fission fragments, percentage of the cross-section for symmetric and asymmetric fission fragments, the ratio of the cross-sections of the symmetric and asymmetric fission fragments and fission barrier as a function of the incident energy have been compared. The range of the incident energy which corresponds to the high probability of the compound nucleus process has been obtained. Three angular momentum windows have been realized from the variation of the production cross-section for the light particles, intermediate mass fragments, fission fragments and the total fragments as a function of the angular momentum which correspond to the dominance of a reaction mechanism in that window. The shell closures have been reflected in the fission partition and weaken with the increase of the incident energy along with the loss of odd-even effects. The mode of the reaction depends upon the excitation energy and angular momentum of the compound system.