Experimental cross sections are compared with the results of calculations including all activation channels for the stable isotopes ofMn and Cu, for neutron incident energies below 20MeV as well as up to 40–50MeV. It results that within the former energy range, the model calculations are most sensitive to the parameters related to nuclei in the early stages of the reaction, while the model assumptions are better proved by analysis of the data in the latter energy range.