Angular correlations near the Fermi energy

Angular correlations between light particles have been studied to probe the extent to which a thermally equilibrated system is formed in heavy ion collisions near the Fermi energy. The results of two experiments are reported. Light particle correlations have been measured at energies (35-50 MeV/nucleon) near the fermi energy. Light particle spectra and large angle correlations were measured for 40 and 50 MeV/nucleon C + C, Ag and Au. The single particle inclusive energy spectra are well fit by a three moving source parameterization. The correlations were done with tag detectors at Θ = 25 degree and 45 degree with Θ = 0 degree, 90 degree and 180 degree. Coincident particles were detected at Θ = 15 degree-150 degree. The decay of particle unstable states was found to contribute noticeably to the same side in-plane correlations. The two-particle correlations were found to be dominated by momentum conservation effects. Light particle correlations at small relative momentum were measured for 25 and 35 MeV/nucleon N + Ag and single particle inclusive spectra were measured for 35 MeV/nucleon N + Ag at Θ = 35 degree, 45 degree, 60 degree and 80 degree. Source radii were extracted from the two-particle correlation functions and were found to be consistent with previous measurements using two-particle correlations and the coalescence model. The populations of particle unstable states were extracted and used together with the measured single particle inclusive spectra and previously measured γ and neutron emitting states to determine the temperature of the emitting system using the quantum statistical model. The temperature extracted from the relative populations of states, using the quantum statistical model, was found to be 4.8-2.4+2.8 MeV which is substantially lower than the 14 MeV temperature extracted from the slopes of the kinetic energy spectra