The formulation of threshold reaction systematics

Using an analysis of existing experimental (n,np), (n,d), (n,t) and (n,α) threshold reaction data for incident neutron energies between 14 to 15 MeV and the theoretical representation of the interaction mechanism of neutrons with atomic nuclei, a set of semi-empirical equations, designed for the evaluation of these threshold reactions, are proposed. The derivation of these equations is based on the relationship of the pre-equilibrium hybrid exciton and evaporation models. In comparison with empirical systematics made earlier by other authors, the proposed formulas provide a better agreement between experimental data and theory. (author). 37 refs, 17 figs, 9 tabs