Selection of violent collisions by means of a neutron calorimeter for interferometry measurements

Two-particle correlation measurements can be used to study heavy-ion collisions at intermediate energy to obtain information on the space-time characteristics of the emitting source as well as on the temperature deduced from the population of excited states. Improvement in this approach can be obtained by selecting the involved impact parameter interval. An experiment is described, in which a 208Pb beam at 29 MeV per nucleon on a 93Nb target was used. The aim of the experiment is to choose experimental conditions to observe mainly light particle correlations coming from heavy equilibrated quasi-projectile nuclei and to sort the events in several intervals of reaction violence. It is demonstrated that one can use a high efficiency 4π neutron detector as a calorimeter and gain with such an instrument high selectivity on the violence of a collision. (K.A.) 17 refs.; 5 figs.; 1 tab