Figure 2.
Scheme of the high-sensitivity OSL (HS-OSL) system tested to improve the light collection of the sample's luminescence. The system consists of: i) blue or green laser for optical stimulation, properly filtered in each case (GG-420 and OG-515, respectively), and defocusing lens, ii) light collection system composed of an ellipsoidal mirror (rhodium coated) and focusing lens to collect the maximum luminescence from the sample; and iii) detection optics composed of a UV transmitting (Hoya U-340 filter) to cut the stimulation wavelength and a PMT (Electron Tubes, model 9235QB).