MODERN PHYSICS LETTERS A, vol.19, no.21, pp.1597-1614, 2004 (SCI-Expanded)
In this study, neutron-emission spectra produced by (n, xn) reactions on nuclei Th-232 have been calculated. Angle-integrated cross-sections in neutron induced reactions on targets Th-232 have been calculated at the bombarding energies from 2 MeV to 18 MeV. We have investigated multiple pre-equilibrium matrix element constant from internal transition for Th-232 (n, xn) neutron emission spectra. In the calculations, the geometry dependent hybrid model and the cascade exciton model including the effects of pre-equilibrium have been used. Pre-equilibrium direct effects have been examined by using full exciton model. In addition, we have described how multiple pre-equilibrium emissions can be included in the Feshbach-Kerman-Koonin (FKK) fully quantum-mechanical theory. By analyzing (n, xn) reaction on Th-232, with the incident energy from 2 MeV to 18 MeV, the importance of multiple pre-equilibrium emission can be seen clearly. All calculated results have been compared with experimental data. The obtained results have been discussed and compared with the available experimental data and found agreement with each other.