Dependence of luminescence sensitivities of quartz on α–β phase inversion break temperatures

To elucidate the luminescence characteristics, including differences in luminescence sensitivity and TL colour (red-TL; RTL and blue-TL; BTL), synthetic and 32 natural quartz samples from different origins were investigated with respect to seven kinds of impurity content (Al, Ti, Li, Fe, Mg, Cu and Ge) and α–β phase inversion break temperatures. Concerning the inversion temperatures, all natural samples exhibited lower inversion temperatures than pure synthetic quartz (573∘C), since high Al impurity content causes lower inversion temperatures. In particular, the inversion temperatures of RTL-quartz moved to much lower temperatures compared with those associated with BTL. Consequently, the RTL- and BTL-quartz were classified at a boundary temperature of 572∘C. In addition, the BTL sensitivities from natural and synthetic quartz samples showed a negative relationship with the Al contents above a few tens of ppm, while the RTL and OSL sensitivities rapidly increased with above 300ppm Al content. The RTL sensitivities increased proportionally to the approximate square of the Al content, strongly suggesting that two Al impurities within a short distance co-operate as a RTL hole centre.