Luminescence of KI under X-ray irradiation

Summary  The X-ray induced luminescence of KI has been investigated in the range from 200 to 600 nm, at temperatures from −180° to 80 °C. Changes in the intensity and spectral distribution of the luminescence are studied, as a function of the irradiation time, and under the influence of plastic deformation, additive coloration, heat treatments. Heating in vacuum induces a 400 nm emission band, which is practically absent in « as received » crystals; plastic deformation and heating in air enhances the 515 nm emission band, otherwise very weak. The dependence of intensity on the X-ray dose and the consequences of various heat treatments suggest that the 515 nm emission is due to a colour centre associated with an oxygen impurity.