Latent track formation is a major effect of the interaction of energetic ions with solids. Formative tracks can be revealed by applying many different techniques like chemical etching

electron microscopy

Rutherford backscattering etc. The size and the topography of these tracks are characteristic for the definite ion-solid interaction as well as the deexcitation process. The information on microscopic mechanism can be obtained by studying how the track size changes as a function of the ion energy and various target parameters. This paper intended to give a representative review of investigations dominated by electronic energy loss

including the track formation

the observation techniques

the significant results obtained and the latest progress.