Fission fragment angular distributions for neutron fission of 232Th and their interpretation with a triple-humped fission barrier

The fission fragment angular distributions have been measured for the neutron fission of ²³²Th at a number of energies near the neutron threshold. An exhaustive search has been made for a set of transition states and barrier parameters that would simultaneously fit the angular distributions and reproduce quantitatively the structure seen in the neutron fission cross section. No satisfactory fit to both types of data could be obtained with a double-humped fission barrier. However, use of a triple-humped fission barrier does provide a reasonable fit to all the experimental data.