Characterization of nuclear sources from neutron-neutron, proton-proton and neutron-proton correlation functions

Two-neutron, two-proton and neutron-proton correlation functions have been measured simultaneously for the E/A = 45 MeV Ni-58 + Al-27 reaction. Calculations from a statistical model have been compared to singles energy spectra as well as to total and gated correlation functions. This imposes very strong constraints on the model parameters. The use of directionally gated correlation functions helps to disentangle space and time information. Values of Gaussian radii, emission lifetimes, initial temperatures, source velocities and flow velocities are extracted. Correlation functions gated on total momentum of the nucleon pairs suggest that more energetic particles are emitted on a fast time scale (< 100 fm/c) and that the fraction of pre-equilibrium to equilibrium emission is larger for protons than for neutrons. (C) 2000 Elsevier Science B.V. All rights reserved.