Angular distributions and cross sections of fragments from neutron-induced fission of 232Th

Abstract

Fission fragment angular distributions and cross sections were measured for the fission of 232Th induced by mono-energetic neutrons of energies 1.20±0.02, 1.40±0.02 and 1.60±0.02 MeV. The fission fragments are detected with approximately 2π geometry with a polycarbonate resin detector. The fission cross section and angular distribution are both changing markedly with neutron energy. Information on the single-particle levels in the transition nucleus 232Th is derived by fitting the experimental data with a Hauser-Feshbach type calculation which includes, in addition to the fission channels, the open neutron and gamma-ray decay channels taking into account level-width fluctuations.