Measurement and theoretical analysis of neutron-induced neutron-emission reactions of (sup 6)Li at 10 to 20 MeV region

摘要

We have measured the neutron elastic and inelastic scattering double- differential cross sections of (sup 6)Li at incident neutron energies of 11.5, 14.1 and 18.0 MeV. Based on this data, together with information from other works, a phenomenological neutron optical model potential (OMP) of (sup 6)Li was constructed to describe the total and elastic scattering cross sections from 5 MeV to several tens MeV. This potential also describes well the inelastic scattering to the 1st excited state (E(sub x) = 2.186 MeV) via the DWBA calculation with the macroscopic vibrational model. The continuum neutron energy spectra and angular distributions were then analyzed by the theory of final-state interaction extended to the DWBA form, with the assumption that the d-(alpha) interaction is dominant in the 3-body final state consisting of n, d and (alpha) particles. Such a calculation was found to be successful in explaining the major part of the low-excitation neutron spectra and angular distribution down to the Q-value region of -9 MeV, except for the Q-value range where the n-(alpha) quasi-free scattering will give a non-negligible contribution at forward angles. (author). 60 refs.