Measurement of fission excitation function for 19F+194, 196, 198Pt reactions

Experimental fission cross-sections are reported for the F-19 + Pt-194,Pt-196,Pt-198 reactions populating an isotopic chain of compound nuclei comprising both closed and non-closed shell nuclei. The fission cross-sections are obtained at near and above Coulomb barrier energies by measuring fission fragment angular distributions. The present work aims to estimate nuclear dissipation and find its isotopic and shell closure dependence from statistical model (SM) analysis of experimental data. Pre-scission neutron multiplicity data for the same systems is also included in the SM analysis. An updated version of SM is used in the present analysis, which includes shell corrections in level density and fission barrier as well as the effect of collective enhancement of level density and orientation effect of the compound nucleus along the symmetry axis. An isotopic dependence of the dissipation strength fitting the fission excitation functions is observed. The pre-scission neutron multiplicity, however, is underestimated by the SM.

Automated summary

Experimental fission cross-sections for the F-19 + Pt-194, Pt-196, Pt-198 reactions were reported, aiming to estimate nuclear dissipation and determine its isotopic and shell closure dependence. The analysis revealed an isotopic dependence in the dissipation strength fitting the fission excitation functions, while underestimating the pre-scission neutron multiplicity.