Momentum transfer study of the reactions induced by light particles (p, d, α) between 70 and 1000 MeV

Angular distribution and correlations of fission fragment induced by light projectiles (p,d,α) on 232Th and 197Au targets from 70 to 1000 MeV have been measured. The distributions of the forward component of the linear momentum imparted to the target nucleus are deduced. They give information about the dominating process leading to fission on a wide range in energy. We propose a classification into three different regimes. Analysis is made with two high energy models: - intra-nuclear cascade model, in which the collison is described with incoherent successive nucleon-nucleon collisions; - a model, called absorption, which is an extension of the fireball model, completely developped by ourself. One of the main results of this analysis is that at twice the Fermi energy the collective effects must be take into account for light projectiles