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A study of peripheral nuclear collisions at Fermi energies with transport models is presented. It is motivated by experiments devoted to studying of isotopic yields in the reactions 18O on 9Be and 181Ta at E/A = 35 MeV measured at very forward angles. The data show a two-component structure, one centered at beam velocity (“direct component”) and another at lower velocities (“dissipative component”). It is shown that the transport calculations describe the general features of the dissipative component of the reaction. In our calculations we take into account the evaporation of the excited, primary projectile-like residues due to statistical decay. This improves the comparison of the results of the calculations with experiment. We find substantially different behavior of the dissipative component in the reactions with light and heavy target.

The neutron time of flight (n_TOF) facility at CERN is a neutron spallation source, its white neutron energy spectrum ranges from thermal to several GeV, covering the full energy range of interest for nuclear astrophysics, in particular for measurements of the neutron capture cross-section required in s-process nucleosynthesis. This contribution gives an overview on the astrophysical program made at n_TOF facility, the results and the implications will be considered.

Heavy ion collisions in the Fermi energy regime may simultaneously show features of direct and dissipative processes. To investigate this behavior in detail, we study isotope and velocity distributions of projectile-like fragments in the reactions 18O (35 MeV/A) + 9Be(181Ta) at forward angles. We decompose the experimental velocity distributions empirically into two contributions: a direct, ‘break-up’ component centered at beam velocity and a dissipative component at lower velocities leading to a tail of the velocity distributions. The direct component is interpreted in the Goldhaber model, and the widths of the velocity distributions are extracted. The dissipative component is then successfully described by transport calculations. The ratio of the yields of the direct and the dissipative contributions can be understood from the behavior of the deflection functions. The isotope distributions of the dissipative component agree qualitatively with the data, but the modification due to secondary de-excitation needs to be considered. We conclude that such reactions are of interest to study the equilibration mechanism in heavy ion collisions.