Impact parameter dependence of light charged particle production in 25A MeV 16O on Tb, Ta, and Au and 35A MeV 14N on Sm and Ta

The impact parameter dependence of light charged particle (p,d,t,α) emission has been studied using an impact parameter selection based on coincident detection of residues or fission fragments. The energy spectra at twelve angles between 20° and 150° have been fit by a multiple moving source parametrization. The angle and energy integrated preequilibrium proton multiplicities decrease with increasing impact parameter in qualitative agreement with a Fermi jet calculation. The preequilibrium d/p and t/p multiplicities increase slowly with increasing impact parameter and are nearly identical at the two bombarding energies. The preequilibrium α/p ratio shows a less consistent dependency on impact parameter but decreases significantly with increasing bombardment energy. A calculation of the d/p and t/p multiplicity ratios with a transport model incorporating complex particle emission is quite successful in reproducing the absolute magnitude, impact parameter dependence, and bombarding energy dependence of the experimental total multiplicities.