Abstract
Thermoluminiscence measurements were performed on samples of yellowish Brazilian Topaz from Acari, MG. Virgin samples revealed peaks 2 and 4 at about 150 and 300°C. respectively, while in samples with extra dose of y-rays, we observed another peak at 80°C. When topaz samples were thermally treated, peak 4 vanished and peak 3 at about 180°C, became visible. Isothermal decay of peak 2 performed on virgin samples showed that peak 3 is present on this samples too. The spectra of the first 3 peaks are very similar in the range of 350 to 500 nm indicating that the recombination processes related to these 3 peaks could be the same. The dose dependency of the TL intensity of the first 3 peaks was mesured from 0.5 to 400 Gy and it sems to start saturating above 400 Gy.