Abstract
The luminescence of γ-rayed KCl crystals induced by plastic deformation is found to occur during loading from a stress lower than the elastic limit to the break down stress of the crystal. A similarity between the stree-strain curve and the load-luminescence curve is established. A luminescence yield stress of the irradiated crystals can be determined from the load-luminescence curves. Studies on slip band formation, pre-irradiation treatment of the crystals, and the effect of rate of load application are presented. A qualitative information about the nature of the luminescence produced during the deformation is given. A tentative model of the luminescence phenomenon from the start of the elastic deformation up to the stress under which the crystal is heavily deformed is presented. The model is based on the fact that the regions around dislocations contain a higher concentration of color centers than the average concentration in the bulk. The instability introduced to the regions of high concentration of color centers produces a considerable amount of luminescence. Spikes of luminescence produced at high stresses are due to the formation of slip bands.
