Small angle neutron-neutron correlations have been measured for the E/A=45
MeV Ni-58+Al-27, Ni-nat, and Au-197 reactions. Two-neutron correlation func
tions, both integrated and gated on the total momentum of the neutron pair,
have been constructed. In order to explain these data, a fraction of fast
''dynamical" emission is needed in addition to slower evaporative emission.
The overall emission time scale is shorter for the symmetric system, indic
ating that the dynamical component is stronger in this case.