Theory of diffusion-controlled defect aggregation under irradiation: A comparative study of three basic approaches

Recent advances achieved within the framework of three basic theoretical approaches to the diffusion-controlled clustering of similar defects during irradiation are compared. These approaches (which can be identified as respectively macroscopic, mesoscopic and microscopic formalisms) have in common that they predict the existence of a critical dose rate for aggregation which increases with temperature, and a bell-shaped temperature dependency of the aggregation rate. Mesoscopic and microscopic approaches demonstrate that the elastic interaction between radiation defects plays a decisive role in the aggregation process. Results which are obtained via the different approaches are illustrated for NaCl crystals.