Simulation of 14 MeV neutrons by protons of higher energies

The effects of 14-MeV neutrons on many materials may be simulated by higher energetic protons which often exhibit very similar cross sections for nuclear reactions and for scattering (except for very small transferred energies). Experiments are carried out to determine production and recoil emission (in forward and backward directions) of radioactive products in niobium, with proton energies ranging from the reaction threshold, 6 MeV, to above 20 MeV. Activation cross sections are measured by the stacked-foil technique with thin targets. Some of the numerical results relevant to radioactive recoil atom sputtering (forward) induced by protons of different energies are summarized in tabular form. Further irradiations are performed with 250-micron thick Nb disks for measuring sputter yields in forward and backward directions. For comparison, a theoretical analysis of both recoil emission and sputter yields is made. The results for single primary knock-ons and for the total elastic and inelastic PKA-spectra are plotted.