Effect of Thermal Pretreatment on the Thermoluminescence of KCl Crystals

Thermal pretreatment was found to enhance the thermoluminescence of x-colored KCl crystals. The effect was found to penetrate into the crystal by diffusion from the outer surfaces. It is affected by the atmosphere surrounding the heated crystal, and it seems also to be structure sensitive. For some crystals the enhancement in the thermoluminescence was by a factor as high as 4000 when the number of quanta emitted during the thermoluminescence was about the same as the number of $F$ electrons bleached during this process.