Systematic Investigation of Fission timescale and Fission Time Distributions Using a Langevin dynamical model

Fission time scale and associated Fission time distributions (FTDs) provide important information on the dynamical evolution of nuclear fission and the competition between particle evaporation and fission. In the present work, a one-dimensional Langevin dynamical model is employed to investigate the fission time scale and corresponding FTDs of the representative compound nuclei 172 Yb, 213 Fr, and 244 Cm. The resulting FTDs exhibit distinct characteristics in the shapes and widths of the distributions, characterized by extended long-time components that significantly impact the average fission time. Further, to understand the transitional behaviour, 213 Fr is studied in detail over a wide range of excitation energies. The excitation-energy dependence of the FTD and the relationship between the average fission time and the last-neutron evaporation time are analyzed to investigate the competition between neutron evaporation and fission. The results provide insight into the excitation-energy dependence of fission-time distributions and the competition between neutron evaporation and fission within the one-dimensional Langevin framework.