Double-Differential Neutron Emission Cross-Section Measurements of Li and Li at Incident Neutron Energies of 8.17 and 10.27MeV

摘要

Energy angular neutron emission double-differential cross sections (DDXs) of Li and Li were measured at incident neutron energies of 8.17 and 10.27 MeV, respectively, using normal and normal + abnormal fast neutron time-of-flight (TOF) spectrometers. The effects of breakup neutrons from a D(d,n) source and the influence of an aluminum container of Li samples, as well as Li in the Li sample and Li in the Li sample, on the secondary neutron spectra were eliminated. The data were derived by comparing the net TOF spectra with the calculated spectra using a realistic Monte Carlo simulation. The differential cross sections were determined by comparing the measured and simulated TOF spectra with respect to specific scattering fractions, i.e., with respect to the elastic lines and the resolved inelastic lines related to single levels or level groups, and normalized to n-p scattering. The angular distributions for the Li and Li elastic and inelastic neutron scattering were obtained also. The angle-integrated cross sections were derived for elastic scattering from Li and for the sum of elastic and 0.478-MeV state inelastic scattering from Li. Inelastic scattering cross sections were obtained for the 2.186-MeV state in Li and the 4.652-MeV state in Li. Meanwhile, based on the unified Hauser-Feshbach and exciton model, the calculated results of the DDXs for n + Li were compared with measurements.