A study of pre-equilibrium emission of neutrons in 93Nb(α, xn) reactions

Abstract

With a view to study the pre-equilibrium emission mechanism in α-induced reactions the excitation functions for 93Nb(α, n)96m Tc, 93Nb(α, n)96Tc, 93Nb(α, 2n)95m Tc, 93Nb(α, 2n)95g Tc and 93Nb(α, 3n)94Tc reactions have been measured in the energy range threshold to ≈ 10MeV/nucleon using the activation technique. The measured excitation functions have also been compared with theoretical predictions based on the semi-classical code, which takes into account compound nucleus as well as pre-equilibrium emission. The analysis of the data indicates significant contribution from pre-equilibrium emission at these energies particularly in the high-energy tail portion of EFs. The effect of the variation of the parameters used in the code has been studied. The isomeric cross-section ratios have also been measured. It has been observed that the pre-equilibrium fraction increases rapidly with the increase in α-particle bombarding energy.