Small angle neutron-neutron correlations have been measured for the $E/A=45\mathrm{}\hspace{0.5em}\mathrm{MeV}{\hspace{0.5em}}^{58}\mathrm{Ni}{+}^{27}\mathrm{Al},{\hspace{0.5em}}^{\mathrm{nat}}\mathrm{Ni},$ and ${}^{197}\mathrm{Au}$ reactions. Two-neutron correlation functions, 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, indicating that the dynamical component is stronger in this case.

• Received 19 April 2000

DOI:https://doi.org/10.1103/PhysRevC.62.037603