Pre-scission neutron multiplicity in the S32+W184 reaction

Abstract

The neutron energy spectra in coincidence with both the correlated fission fragments in $^{32}\mathrm{S}+^{184}\mathrm{W}$ reaction forming the compound nucleus $^{216}\mathrm{Th}$ at an excitation energy of 71.31 MeV have been measured at various angles with respect to one of the fission fragments. Pre- and post-scission neutron multiplicities of $2.68\ifmmode\pm\else\textpm\fi{}0.48$ and $3.3\ifmmode\pm\else\textpm\fi{}0.20,$ respectively, have been extracted by analyzing angular correlation of the neutron energy spectra using moving source fitting procedure. The excess pre-scission neutron multiplicity in comparison to statistical model joanne2 code predictions have been converted into total fission delay. A comparative study of fission delay has been carried out for the $^{16}\mathrm{O}+^{208}\mathrm{Pb}$ reaction forming the compound nucleus $^{224}\mathrm{Th}$ at similar excitation energy as in $^{32}\mathrm{S}+^{184}\mathrm{W}$ reaction. Both the reactions have been analyzed within the frame work of joanne2 code including fission delay, deformation dependent level densities, particle binding energies, and transmission coefficients. The observed fission delay for both the reactions can be quantitatively understood if different formation time predicted by dynamical model hicol code are considered.