Thermoluminescence and annealing of F-centres in KCl gamma irradiated at room temperature

Abstract

The thermoluminescence spectrum and phosphorescence decays of Harshaw KCl samples gamma irradiated at room temperature have been studied up to 400 degrees C. For the six peaks found, the order of the kinetics of recombination, the pre-exponential factor and the activation energy have been obtained. It has been observed that the area under the thermo-luminescence curve is always proportional to the F centre concentration in the sample before heating. It was also found that there is an annealing step of F centres corresponding to each thermoluminescence peak, when the temperature of the sample is raised at a constant rate. It is concluded that the F centres play the role of recombination centres in the annealing process, the interstitials being the mobile entities moving towards the recombination centre. At some stage in the process light is emitted. The spectral analysis of this light shows that the emission band has its maximum at 440 mu m for all the thermoluminescence peaks.