As a result of environmental radioactive radiation electrons get trapped in the defects of the crystal lattice of certain minerals. The longer the radiation lasts, the more electrons get trapped. By the method the last time when the mineral was exposed to sunlight or heating can be determined, as these events reset the minerals and free electrons from their traps. Measurements are made either by stimulating the sample with heat (TL) or light (OSL) in order to determine the number of electrons trapped since resetting. The method is primarily applied to date sediments and pottery. Age limits extend from a few decades to several hundred thousand years. 100 – 200 g of sediment and 100 – 200 mg of pottery material is necessary for the measurements. Sample preparation and measurements take 5 – 10 days and 2 – 3 weeks, respectively.