Thermoluminescence and colour centre thermal stability in KCl:Ca and KCl:Sr irradiated at room temperature

The thermoluminescence and the thermal stability of the F and V-centres induced by irradiation in KCl:Ca and KCl:Sr samples have been studied. It has been found that the thermal annealing of both types of colour centres and the thermoluminescence are different aspects of the same basic phenomenon. Namely, as previously proposed, the thermoluminescence is due to the recombination with F-centres of mobile interstitials thermally released from V-centres; at some stage in this process light is emitted. No evidence of thermally stimulated currents has been found. The two types of impurity induce a different pattern of first-order glow peaks. This indicates that each impurity induces several interstitial traps. Their activation energies and pre-exponential factors are given.