COLLECTIVE REACTIONS TO THE CONTINUUM IN NEUTRON-SCATTERING BY NIOBIUM

The preequilibrium cross sections for the direct excitation of collective states, including giant resonances, in the continuum region, are calculated and combined with the multistep direct, multistep compound, and compound nucleus cross sections to give a complete analysis of neutron scattering by niobium. These collective cross sections we calculated in the framework of DWBA. A good description of neutron emission spectra and angular distributions has been obtained at incident energies 14.1, 20, and 25.7 MeV.