LIQUID-DROP MODEL AND EFFECTS OF ELECTRONIC-ENERGY LOSS ON RADIATION-DAMAGE CASCADES

We present two aspects of the thermal behaviour of cascades, related t o the mechanisms of heat transport. The first aspect concerns the PKA energy range where subcascades are produced and discusses the thermal interaction between them. For this description we couple the results o f the Binary Collision Approximation (BCA) to a simplified solution of the heat equation. Comparison with Molecular Dynamics (MD) results wh en available supports this approach. However this analysis only consid ers lattice conductivity, neglecting the possible effects of electroni c transport. In the second part of this presentation we consider the e ffects of the electronic energy loss on the dynamics of thermal spikes in Cu. This study is based on a simple model of the stopping power an d the electron phonon interaction in the framework of the Embedded Ato m Model (EAM) for MD. This approach is only valid for weak-coupling sy stems, like Cu, where we obtain quantitative information on the effect .