Abstract
A comparison between the predictions of different models is tempted on the simple case of a thin foil irradiated with electrons. The agreement and differences between the Monte-Carlo approaches and the cluster dynamics enlighten the necessity, for any future development, of settling down on a firm basis the emission rates from defect clusters. Despite its simplicity, this simple irradiation test shows that vacancy clusters nucleation is favoured in the self interstitial atom denuded zones along the surfaces, promoting the possible growth of particularly large cavities in this very region at later stages.