Breakup density in spectator fragmentation

Proton-proton correlations of protons, deuterons and tritons with alpha particles from spectator decays following 197Au+197Au collisions at 1000 MeV per nucleon have been measured with two highly efficient detector sodoscopes. The constructed correlation functions, interpreted within the approximation of a simultaneous volume decay, dedicate a moderate expansion and low breakup densities, similar to assumptions made in statistical multifragmentation models.