Neutron multiplicity measurements for19F+194,196,198Pt systems to investigate the effect of shell closure on nuclear dissipation

Abstract

Pre- and post-scission neutron multiplicities are measured for the three isotopes of Fr (${}^{217}$Fr, ${}^{215}$Fr, and ${}^{213}$Fr) in the excitation energy range of 48--91.8 MeV. Out of these three isotopes, ${}^{213}$Fr has shell closure (${N}_{C}=126$) while the other two are non-closed-shell nuclei. Statistical model calculations using Kramers' fission width are performed to investigate shell effects on the dissipation strength which fit the experimental data. It is observed that shell correction to the binding energies of the evaporated particles strongly affects the fitted values of the dissipation strength. However, the best-fit dissipation strength is only weakly influenced by the inclusion of shell correction in fission barrier.