Electric field effect on the luminescence of KI:T1

Thermoluminescence of KI: T1, X- or β-irradiated at T ?77°K shows two main peaks at 105°K and 170°K. They are respectively attributed to the recombination of mobile V_K centres with T1^O centres and to the recombination of thermally released electrons from T1^O centres with T1²⁺ centres. Similar experiments performed under static electric fields (E <40kV cm^-1) show that the intensity of the second glow peak is strongly reduced. The relative intensity variation is anticorrelated with the intensity of glow peaks occurring at T > 230 °K. We suggest that in the temperature range in which T1^O centres are thermally ionised, the effect of the electric field is to favour the retrapping of these electrons on other traps (still unknown). Irradiation doses also play an important role and their effects are studied at T = 77 °K and T = 200 °K.