Direct and compound interactions for the neutron-induced fission cross section determination

Recent ratio surrogate data for the neutron-induced fission cross sections are inter-compared for the chain of Th and U nuclides. The structure of the fission barrier and the angular moments of the entrance channel states are shown to be significant. The excitation/position of the Kπ = 2+ abnormal rotational band-head at the inner saddle of even-even U fissioning nuclide like 240U is shown to be critically important. At 231Th nuclide medium excitations of 10–20 MeV, when pre-fission neutron emission is possible in the reaction 232Th(3He, 4He), the excitation of Kπ = 0− states depends on the mass-asymmetry of the even nuclide 230Th saddle shapes. Octupole band states are shown to be relevant for the 232Th(3He, 3He′) reaction. The consistency of surrogate, ratio surrogate and neutron-induced fission data is revisited.