I - The emission spectra of tl produced by ion implanted CaF2

Abstract
Rare earth doping of CaF2 produces material which gives strong thermoluminescence signals. In an attempt to separate the influence of impurity and intrinsic defects CaF2 has been implanted with ions of Ce, Dy, Mn, Ca and F. Comparisons are made with chemically doped samples and the effect of thermal treatments have been made in all cases. The cerium and dysprosium ions influence both the shallow charge trapping levels, which determine the temperature of the glow peaks, and the recombination sites which control the photon spectra. After implantation the strong TL signals show emission at wavelengths near 360 nm for Ce, 480 nm for Dy and for Mn. Re-excitation of the trapping levels reveals selective emission for some defects, restructuring of less stable defects and major changes in defect concentrations with thermal treatment. The effects of the impurity and intrinsic defects on the spectra are discussed. One major observation is that addition of cerium to “pure” samples does not enhance the TL sensitivity, whereas Dy and Mn both show new glow peaks. In the case of Dy it is thought that the charge trap and the luminescent site are directly linked within one complex defect.

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