Neutron multiplicity as a probe to study the nuclear dissipation in heavy ion fusion-fission dynamics

Heavy-ion induced fusion-fission reactions involve many complex processes, which are understood through experimental as well theoretical approach. To investigate these processes, a number of attempts like mass distribution, mass-angle correlations, and mass-gated neutron multiplicity measurements have been done. In recent years, nuclear dissipation has emerged as a topic of considerable interest involved in the fusion-fission process. Nuclear dissipation causes the delay in the fusion-fission process with respect to the statistical picture of the compound nucleus (CN) decay. To understand the nuclear dissipation, neutron emission is one of the preferable probes. It helps in measuring the time-scales of these processes and in understanding the mechanism of energy dissipation in heavy ion reactions. In the literature, measurements of neutron multiplicity have been reported to investigate the effect of entrance channel mass asymmetry, neutron shell closure, N/Z, etc. in the fission process. In the present study, we have measured the neutron multiplicity for the reaction ¹⁸O + ¹⁸⁶W populating the compound nucleus ²⁰⁴Pb to understand the dissipative fission dynamics. We have studied about the effect of entrance channel parameters on the nuclear dissipation. (author)