Displacement cascades in a borosilicate glass: Influence of the level of polymerization on the cascade morphology

We have performed some molecular dynamics calculations of displacement cascades in a simplified nuclear glass (SiO2 + B2O3 + Na2O + Al2O3 + ZrO2). We have observed that the damaged volume at the end of the collision sequence can be divided into a so called highly damaged volume and lightly damaged volume. The aim of this paper is to propose an explanation of this phenomenon by considering that some regions are easy to cross by the projectile and others are difficult to cross by the projectile. Regions which are easy to cross correspond to those containing Na atoms with a low level of polymerisation, and regions which are difficult to cross are areas containing Na atoms with a high level of polymerisation. (orig.)