Temperature Dependence of Positron Trapping by Defects in Solids

The temperature dependence of positron trapping in metals containing defects was analyzed. Positron trapping by voids in a metal increases with increasing temperature while trapping by dislocation loops decreases with increasing temperature. But positron trapping at vacancy defects differ from both of them. Trapping at vacancy defects gives rise to a negative temperature coefficient whereas trapping in the presence of strain-induced dislocations produces a positive temperature coefficient for the same lifetime component. Thus the temperature dependence of positron trapping is an additional method for the identification of defects, being particularly useful to the study of dislocations.