Preequilibrium (n,n) cross sections on nuclei around atomic number 50 at En=14.1 MeV

The energy spectra of neutrons emitted from 14.1-MeV-neutron-induced reactions on Ag, Cd, In, Sn, Sb, and Te were measured at 70° in order to investigate the shell and odd-even effects in the preequilibrium (n,n) process. The cross sections integrated over the outgoing energies of 710 MeV, where the preequilibrium process is dominant, increased monotonically with increasing atomic numbers of all scatterers except Te. The results of calculations based on the exciton model showed an underestimation in 710 MeV only for Te. This underestimation could be explained by taking into account the contribution from the collective excitations of the low energy octupole resonance by the direct process. As a result, it was found that there were no appreciable shell and odd-even effects in the preequilibrium (n,n) process that leaves the residual nucleus into the continuum region.