Eur. Phys. J. A (2007) 31: 43-51
https://doi.org/10.1140/epja/i2005-10318-5

Regular Article - Nuclear Structure and Reactions

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

¹ Department of Physics, Aligarh Muslim University, (UP)-202 002, Aligarh, India
² Department of Physics, DSN College, (UP)-209 801, Unnao, India

Received: 20 June 2005
Accepted: 23 November 2006
Published online: 22 January 2007

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.