Spallation neutron emission spectra in medium and heavy target nuclei by a proton beam up to 140 MeV energy.

In this study, neutron-emission spectra produced by (p,xn) reactions for some spallation neutron target nuclei such as (65)Cu, (204,206,207,208)Pb, (209)Bi, (232)Th and (238)U have been calculated by a proton beam up to 140 MeV. Multiple pre-equilibrium mean free path constants from internal transition for (204,208)Pb (p, xn) neutron emission spectra have been investigated. In the calculations, pre-equilibrium effects were calculated by using new evaluated hybrid model and geometry dependent hybrid model, full exciton model and cascade exciton model. The reaction equilibrium component was calculated by Weisskopf-Ewing model. The obtained results have been discussed and compared with the available experimental data and found agreement with each other.

Application of asymmetry depending empirical formulas for (p,n alpha) reaction cross-sections at 24.8 and 28.5 MeV incident energies.

In this study, we have investigated the asymmetry term effect for the (p,n alpha) reaction cross-sections and we have obtained new coefficients for the (p,n alpha) reactions at 24.8 and 28.5 MeV energies. We have suggested empirical formulas including the new coefficients found by fitting two parameters for proton induced reactions. The coefficients were determined by least-squares fitting method. The obtained cross-section formulas with new coefficients have been discussed and compared with the available experimental data.