Thirty years ago, the sharp development of the nuclear phy- SlCS has given scope to some connected areas such as radiochemis try, radiobiology, radioprotection, radiation damages. In this last subject - damages induced by radiations in mate rials, the earlier studies are essentially connected to the me chanism of defect creation. Several workers, for instance, SEITZ (1949), DIENES and VINEYARD (1957), BILLINGTON and CRAWFORD (1961) have developed the first approach in the damage processes theories. In the 65th years a "saturation effect" occurs in the studies of the mechanisms and correlatively a strong development appears in the physics of the defect itself. If it is possible in many cases to study defects without a good ~nowledge of their origin many researchs, in particular in the field of defects induced by energetic heavy ions, needs a better understanding of the damage processes. The track phenomena for instance is of special interest in heavy ions problems, cosmic ray tracks in lunar and meteorite crystals or glasses are a good indicator of the solar activity. On the other hand, color centers, induced by energetic heavy ions in alkali-halides crystals, shown a quite different behaviour than those created by light particles, it is necessary to assume that the ionic bombardement creates centers in a well located re gion : a core around the path of the incident particle.
