PARTICLE-PARTICLE CORRELATIONS - INDEPENDENT PARTICLE-EMISSION VERSUS SEQUENTIAL DECAY OF HEAVY FRAGMENTS

Particle-particle coincidence measurements for both large and small separation angles are reported for the reactions 140 MeV O-16 + Al-27-->p-p, p-d, d-d, alpha-alpha, d-alpha, and p-alpha. Two clusters of seven detectors were used at +/-50-degrees, on both the right and left sides of the beam axis. Coincidence data were compared for nearest-neighbor and across-beam geometries. For p-p, p-d, and d-d pairs, the results of this symmetry test are consistent with independent particle evaporation. For the alpha-alpha, d-alpha, p-alpha pairs, the results indicate significant contributions from breakup of preformed fragments. These results suggest that small-angle correlations for the former pairs are useful as probes of the space-time extent of the emitters, but that the latter pairs are compromised for this task.