Point defects and the pre-dose effect in natural quartz

As part of a study to define more precisely the 'pre-dose effect' in natural quartz, we have used thermoluminescence (TL) and electron spin resonance (ESR) in an attempt to identify the defects responsible for the 100 C TL peak. The samples used were found to contain aluminium, germanium, titanium, lithium and hydrogen impurities. Correlations were made between the size of the TL peak following a series of irradiations at room temperature and at -196 C, and ESR signals produced following a similar series of irradiations. Additionally, isothermal decay measurements of both the TL and the ESR at room temperature were made. The results suggest that electrons are released from Ge4+ - e- centers to recombine at Al3+ - h+ centers and at unidentified hole centers to produce TL at 100 C, with wavelengths of 470 and 380 nm, respectively. (author)