TL spectra of natural zircons

The TL emission spectra of zircon are dominated by line features near 380, 480 and 580 nm characteristics of rare earth impurities. Variations in TL signals from Dy³⁺, Tb³⁺ and Eu³⁺ impurities are seen in samples from different regions. In a detailed study of green zircons it is noted that the TL spectra and relative intensities of component glow peaks alter with storage after irradiation. This complex defect interaction results in the so-called anomalous fading in some spectral regions and signal enhancement in others. Defects associated with Dy³⁺ and Tb³⁺ behave differently. Defect models of some of the centres in the zircons are discussed.