Mass and charge transfer in the heavy ion reactionsNi208andNi208

Abstract

Target-like reaction products corresponding to the transfer of one or several nucleons have been measured as a function of the total kinetic energy loss in the reactions ${}_{}{}^{208}{}_{}{}^{}\mathrm{Ni}$ (1215 MeV) and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Ni}$ (1107 MeV) with a focusing time-of-flight spectrometer which provided a unique mass and charge separation and good energy resolution. The analysis of the experimental data covered the range from elastic scattering to deep-inelastic collisions. In the quasielastic region, neutron transfer dominates. The transfer probabilities as a function of the distance of closest approach can be described by a semiclassical theory of tunneling. Quasielastic transfer from the Ni targets to the ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ projectile is strongly inhibited by the reaction Q values. For the intermediate and deep-inelastic collisions, the mean values and variances of the mass and charge distributions as a function of the dissipated energy, as well as the correlations between neutron and proton transport, are discussed in a statistical diffusion theory. The important influence of the static potential energy surface on nucleon transport in the deep-inelastic region is demonstrated. Deviations from the simple diffusion model, observed at small to medium energy losses, are discussed.