Study of the 237 Np(n,f)-reaction at MeV neutron energies Original Research Article

The fission fragment properties of the reaction 237 Np(n, f ) have been investigated at IRMM in the neutron energy range En=0.3 to 5.5 MeV. Above En=0.5 MeV, the View the MathML source averaged over all fission fragment masses shows a continuously decreasing trend. The observed variations in the View the MathML source as a function of the compound nuclear excitation energy have been attributed to a combination of the changes in the mass yield and View the MathML source distributions. A description of the two-dimensional mass–TKE distributions has been obtained in terms of fission modes in the frame of the multimodal random neck-rupture model. The inclusion of the superlong symmetric mode is necessary to explain the observed dip in the experimental View the MathML source close to symmetry.