Neutron activation cross-sections in antimony isotopes were measured at an incident neutron energy of 14.2±0.2 MeV. The versatile mixed powder technique and high resolution Ge(Li) detector gamma ray spectroscopy were employed. The measured cross-sections were compared with those reported in literature. The total (n, 2n) cross-sections were compared with the estimates based on statistical theory. The experimental values were found to be smaller than the statistical theory estimates and the resulting diminution was attributed to the precompound effects in (n, 2n) reactions at 14 MeV.

With a view to study the pre-equilibrium effects in neutron-induced reactions, the activation cross-sections for (n, 2n) reactions at 14.2±0.2 MeV in the heavy mass region have been measured using the versatile mixed powder technique and high resolution Ge(Li) detection. The experimental cross-sections are found to be consistently smaller than the predictions based on the statistical theory and this is attributed to the effect of pre-equilibrium decay in these reactions. The cross-sections due to pre-equilibrium decay were estimated using exciton, hybrid and unified models. When this cross-section was included in comparing the experimental cross-sections with theory, we obtained better agreement, within the limitations of the present-day preequilibrium theories.