The dependence of the thermoluminescence of LiF: Mg2+ crystals on the state of aggregation of the Mg2+ ions

When LiF crystals containing a low concentration of Mg 2+ ions are irradiated with γ-rays and then heated, five glow peaks may be observed. The intensity of dielectric absorption is used as a monitor of the state of aggregation of the Mg 2+ -vacancy pairs. It is shown that one of the factors determining the heights of peaks 2 and 3 is the concentration of dipoles in the crystal at the time of irradiation; those Mg 2+ -vacancy pairs present in trimers and larger aggregates make no contribution to the height of these peaks. Both dipoles and trimers contribute to the traps responsible for peaks 4 and 5, but aggregates containing more than three Mg 2+ -vacancy pairs do not contribute. Previous work based on the assumption of a direct proportionality between dipole concentration and the height of peak 2 is invalid.