Focusing in Collision Problems in Solids

Abstract

In treating problems of sputtering and radiation damage of solids, a billiard ball model is frequently assumed. An attempt is made to indicate to what extent such a model is justified. Using this model it is noted that the lattice structure of a crystal implies a correlation between successive collisions in a damage process which can lead to the propagation of an energy pulse, or a sequence of collisions, along a close-packed line of atoms. The rate of attenuation of these pulses is estimated for a particular case and certain implications of the effect are discussed.