What is an optically stimulated luminescent (OSL) dosimeter?

• A. An active dosimeter that provides real-time readings.
• B. A device for calibrating survey meters.
• C. A type of scintillation detector.
• D. A passive dosimeter that stores energy and emits light when stimulated by light to read dose.

Answer: (D)

OSL dosimeters are passive devices that record radiation exposure by trapping charges in a crystal lattice during irradiation and storing that information until read. When you read them, a reader shines light on the material, releasing the trapped energy as luminescent light. The amount of light emitted is proportional to the absorbed dose, allowing you to determine how much radiation was received. This means there’s no real-time readout in the field—the device doesn’t produce an immediate dose signal while exposed. They are distinct from scintillation detectors, which emit light instantly in response to radiation. A common material used is aluminum oxide doped with carbon (Al2O3:C).