Measurements of double-differential neutron emission cross-sections of 238U and 232Th for 2.6, 3.6 and 11.8 MeV neutrons

Abstract

Double-differential neutron emission cross-sections (DDXs) of 238U and 232Th were measured for 2.6, 3.6 and 11.8 MeV incident neutrons using a time-of-flight (TOF) method at the Tohoku University 4.5 MV Dynamitron accelerator facility. In DDXs for En=2.6 MeV, discrete structures by vibrational level groups are visible clearly around excitation energy (Ex) around 0.75 and 1.15 MeV, while inelastic scattering to continuum-levels become dominant at En=3.6 MeV for both nuclei. For En=11.8 MeV, continuum structures with strong forward peaking are dominant with some discrete structures at around 0.7–4.0 MeV excitation energy for both of 238U and 232Th. Partial cross-sections for the elastic and inelastic scattering processes were also derived from the DDX data.