Optically Stimulated Luminescence (OSL) characteristics of seven different color types of quartz samples under 470 and 405 nm stimulation

This study investigates the Optically Stimulated Luminescence (OSL) characteristics of seven distinct color varieties of natural Brazilian quartz to characterize their charge-storage mechanisms relevant to radiation dosimetry. OSL measurements were performed using Blue Stimulated Luminescence (BSL) at 470 nm and Violet Stimulated Luminescence (VSL) at 405 nm. OSL component analysis utilized the Pseudo-Linear Modulation technique to determine the photoionization cross-section (σ) for each resolved trap. The results indicate that the OSL response is highly heterogeneous and dependent on both the sample's coloration and the stimulation wavelength. Crucially, a non-correlation was established between the integrated TL intensity and the OSL signal intensity, suggesting that the charge trap populations accessed by thermal and optical means are not universally shared across all quartz varieties. The VSL method proved superior for trap resolution, consistently detecting one or two more components per sample than BSL, underscoring the shorter wavelength's ability to probe deeper traps. Quantitative analysis confirmed low occupancy of conventional slow traps and, significantly, identified three novel photoionization cross-sections (C3, C6, and C8) unique to these colored mineral quartz samples. Furthermore, for specific components of some colored quartz varieties, the cross-section at 470 nm exceeded that at 405 nm, indicating that photo-eviction efficiency is not strictly monotonically increasing function of photon energy. Instead, it is modulated by the specific trap kinetics and spectral sensitivity inherent to the mineral´s impurity-related defect structures. • Thermoluminescence (TL) intensity does not correlate with OSL signal intensity, indicating that the charge trap populations are not universally shared across all quartz varieties. • Violet Stimulated Luminescence (VSL) at 405 nm consistently resolves one to two more luminescence components than BSL (470 nm). • OSL results show low and inconsistent occupancy of conventional traps (medium, slow 1 through slow 4), highlighting the complexity and heterogeneity of charge storage mechanisms in colored quartz. • Pseudo-LM-OSL analysis resolves three novel photoionization cross-sections (σ 3 , σ 6 , σ 8 ) not found in conventional sedimentary quartz. • The photoionization cross-section 3 is found exclusively in the green quartz sample under blue stimulation.