DEFECT PRODUCTION IN HIGH-ENERGY CASCADES - THE ROLES OF MOLECULAR-DYNAMICS AND BINARY COLLISION SIMULATIONS

The processes of radiation damage, from initial defect production to m icrostructure evolution, occur over a wide spectrum of time and size s cales. An understanding of the fundamental aspects of these processes requires a spectrum of theoretical models, each applicable in its own time and distance scales. As elements of this spectrum of models, mole cular dynamics and binary collision simulations play complementary rol es in the characterization of the primary damage state of high energy collision cascades. Molecular dynamics is needed to describe the indiv idual point defects in the primary damage state with the requisite phy sical reality. The binary collision approximation is needed to model t he gross structure of statistically significant numbers of high energy cascades. Information provided by both models is needed for connectin g the defect production in the primary damage state with the appropria te models of defect diffusion and interaction describing the microstru cture evolution.