Neutron energy spectra produced from thick targets by light-mass heavy ions

The measured neutron energy spectra produced from thick targets by light-mass heavy ion beams were analyzed with the phenomenological hybrid of equilibrium and pre-equilibrium emissions. The neutron energy spectra are fitted to two (in the energy region of incident projectile energy lower than 100 MeV) and three (in the energy region of incident projectile energy higher than 100 MeV) Maxwellian-type components. The lowest energy component corresponds to the evaporation neutrons from a compound nucleus having a nuclear temperature independent of the neutron emission angle and the higher two components to the pre-equilibrium neutron emission having a nuclear temperature depending on the angle. (orig.)