This prevents exposure of the grains to light, a process known as bleaching, which would lead to the light-sensitive OSL traps being emptied and the OSL “clock” being reset. The most typical would be to hammer opaque plastic or metal tubes into a cleaned section wall; the sediment at both ends of the tube will then be discarded in the lab, and the inner light-safe portion will be used for the measurement of the OSL signal.
The ISGS OSL dating lab is equipped with a Risø TL/OSL-DA-20 Reader; Gamma Spectrometers; two amber light prep labs with fume hoods, shatter box, auto-grinding mortal, dry oven, and furnaces. Above Right: ISGS Risø TL/OSL-DA-20 Reader in dark lab Above Left: ISGS Gamma Spectrometry Lab.Above Right: Auto-grinding mortal and Merinelli Beaker Above Left: Furnaces and shatter box containers. Models and the conceptual framework necessary for an understanding of optically stimulated luminescence (OSL) are described.When these sediments are subsequently cooled and deposited within accumulating sediments, e.g., within a cave, they once again become hidden from sunlight, and the “batteries” begin to recharge (Figure ).In other words, natural radiation sources in the immediate vicinity of the grains will result in the movement of new electrons out of their orbitals and into traps, with the rate of filling being determined by the level of natural radiation.