In an OSL dosimeter, what is the purpose of the optical stimulation?

In an OSL (Optically Stimulated Luminescence) dosimeter, the purpose of optical stimulation is to release stored energy. When exposure to ionizing radiation occurs, the dosimeter captures energy in the form of trapped electrons within a crystalline material, typically aluminum oxide. These electrons remain "trapped" until the dosimeter is stimulated with light, often from a laser.

During the optical stimulation process, the light excites the trapped electrons, causing them to move from their metastable state back to a lower energy state. As these electrons return to their equilibrium state, they emit light, which can then be measured. The intensity of the emitted light is directly proportional to the amount of radiation the dosimeter has been exposed to, allowing for an accurate dose measurement.

This mechanism is what distinguishes OSL technology; the ability to read the stored dose by using optical stimulation is crucial for analyzing radiation exposure without altering the dosimeter's response. Thus, releasing stored energy effectively facilitates the measurement of previous radiation exposure, making this process essential for the dosimeter's function.