ATOMIC EFFECTS IN HEAVY-ION ELASTIC-SCATTERING

Angular distributions of a Pb-208 beam on Pb-208 thin targets at very small angles were measured. The shape of the experimental distribution is not Gaussian, indicating a plural scattering regime rather than mu ltiple scattering. The distribution was well reproduced by a Monte Car lo simulation of the straggling process. For the first time we observe d and quantified the influence of the production of electrons during t he scattering. This effect was observed in the angular correlation of the scattered Pb-208 nuclei detected in kinematic coincidence and also in the limiting angle of the Pb-208 scattered in a Ag-107,Ag-109 targ et. This effect introduces a spread in the scattered angle which is of the same order of magnitude as the angular straggling.