Neutron production in coincidence with fragments from the Ca-40+H reaction at E-lab=357A and 565A MeV

Neutron production, in coincidence with fragments emitted in the Ca-40+H reaction at E-lab=357A and 565A MeV, has been measured using a 3-module version of the multifunctional neutron spectrometer MUFFINS. The mean neutron multiplicities for neutrons detected in the angular range covered by MUFFINS (0 degrees - 3.2 degrees) have been estimated from the comparison between the neutron cross sections, in coincidence with the fragments, and the elemental cross sections. We have found evidence for a preequilibrium emission of prompt neutrons in superposition to a "slower" deexcitation of the equilibrated remnant by emission of nucleons and fragments, as already seen in inclusive rapidity distributions. The energy dependence of die inclusive neutron production cross sections, measured in a previous work, is here interpreted as due to the stronger neutron focusing in the forward direction at the higher energy. Comparison with a BNV+phase space coalescence model is discussed. [S0556-2813(99)01101-2].