Decay of 228Th* Formed Using Radioactive Beam 132Sn at Above Barrier Energies

Abstract

The reactions involving fusion of neutron-rich radioactive ion beam as projectile are of great interest in today’s time. Since N/Z ratio is large, hence the complete fusion of projectile and target nuclei is not the only phenomenon observed in such reactions. Many other processes such as quasi-fission or incomplete fusion are also observed at times. The advantage of studying such systems is that with medium-mass, neutron-rich radioactive nuclei, the influence of neutron excess on fusion and compound nucleus dynamics can be explored, which helps us to improve our understanding on how to synthesize new neutron rich heavy nuclei. In this study, we have concentrated on the study of fusion-fission process only. We have investigated the decay of 228Th* formed in 132Sn+96Zr reaction at above barrier energies in order to analyze the effect of fusion of 132Sn beam with 96Zr target. The calculations have been done in the framework of Dynamical Cluster decay Model (DCM). We have calculated the fission cross-sections in reference to available experimental data. The effect of deformation and orientation is also seen. The decay has been analysed for spherical and the quadrupole (β2) deformed choices of fragmentation. With both of these fragmentation choices, it has been seen that fission fragments are the major contributors towards the decay of 228Th* whereas evaporation residue contribute negligibly small. The calculated cross-sections compare nicely with the available experimental data. The fission fragment distribution is clearly asymmetric for spherical and β2-deformed choices of fragmentation. However, at higher incident energies the symmetric fragments also start contributing, particularly for spherical case. The neck-length parameter “ΔR” decreases as a function of energy.