Precompound emission in the reaction 65Cu(p, xn) and the nucleon-nucleon scattering mechanism☆

Abstract The reaction 65 Cu(p, x n) has been studied with E p = 26.7 MeV for angles 3° ⩽ θ ⩽ 177°0. Whereas the angle-integrated spectrum can be explained by a semiclassical preequilibrium model, the nucleon-nucleon scattering approach fails for the preequilibrium neutron emission at far backward angles. The failure is shown to be due to principal shortcomings. In contrast, the quantummechanical statistical multistep calculations give good agreement with the main contribution for residual energies U