Excitation functions of51V,56Fe,65Cu(p, n) reactions between 10 and 45 MeV

Abstract

The (p, n) reaction cross-sections of51V,56Fe and65Cu have been measured, for incident-proton energies ranging from 10 to 45 MeV, in steps of 2 MeV. The excitation curves exhibit the usual changes in slope consistent with the expectation that the high-energy tails are mainly due to pre-equilibrium neutron emission. These changes occur for proton energies around 20 MeV, a value in accord with the result previously obtained for reactions of the same type in heavier nuclei. A detailed analysis of the excitation curves has been performed under the hypothesis of incoherent addition of the contributions from compound-nucleus evaporation and pre-equilibrium emission. It is concluded that calculations, based, for the pre-equilibrium contribution, on the exciton model, can give results in satisfactory agreement with the experiment even for nuclei with mass numbers as low asA≃50.