Optically Stimulated Luminescence or OSL is the most advanced technology developed by Landauer, Inc. for measuring radiation exposure. Compared to thermoluminescence dosimeters (TLD), which are heated to determine the radiation exposure, OSL dosimeters are exposed to a light source to obtain the amount of radiation absorbed by the dosimeter. OSL dosimetry utilizes the detector material carbon doped aluminum oxide (Al2O3:C) crystals produced by Landauer.