Fission fragment folding angle distributions for the systems11B+237Np,12C+236U, and16O+232Thin the energy range1.1<E/VB<2.1

Abstract

Fission fragment folding angle distributions have been measured for the systems ${}^{11}\mathrm{B}{+}^{237}\mathrm{Np},$ ${}^{12}\mathrm{C}{+}^{236}\mathrm{U},$ and ${}^{16}\mathrm{O}{+}^{232}\mathrm{Th},$ populating the same compound nucleus ${(}^{248}\mathrm{Cf})$ and at similar excitation energies ${(E}_{x}$ 45--100 MeV). The full momentum transfer and incomplete momentum transfer fusion-fission components have been separated over the bombarding energy range $1.1<{E}_{\mathrm{c}.\mathrm{m}.}{/V}_{B}<2.1.$ It is observed that the largest value of the ratio of the transfer fission to the total fission is around 10 to $15%$ at the highest energy investigated. Over the energy range mentioned above, it is found that the transfer fission corrected fission fragment anisotropies are not significantly different from the values already obtained from the analysis of the total fission data reported earlier and hence the conclusions reached from the inclusive data remain unchanged. The anisotropy data were analyzed for the two cases corresponding to fission events with sizable fission barriers ${(B}_{f}>T)$ and with smaller fission barriers ${(B}_{f}<T).$ It was interesting to find that the effective moment of inertia ${(J}_{\mathrm{eff}})$ values deduced from the latter component were consistent with the values from Sierk prescription used in the former case.