OSLdosimeters

OSL dosimeters, or optically stimulated luminescence dosimeters, are passive radiation detectors used to measure ionizing radiation dose. They rely on luminescence emitted by an inorganic crystal when its trapped charge is stimulated by light, typically blue light. The emitted light is proportional to the absorbed dose, allowing dose estimation after reading. The signal can be erased optically and the device reused after appropriate resetting.

The most common material is aluminum oxide, usually doped to form Al2O3-based dosimeters. The two main formulations are Al2O3:C (carbon-doped) and Al2O3:Ti,Mg (titanium/magnesium-doped). These variants differ in sensitivity, linearity, and fading behavior, and other doped or polycrystalline formulations are used for specialized applications.

OSL dosimeters are typically small discs or chips embedded in dosimetry cards or badges. Readout is performed with a dedicated optically stimulated luminescence reader that emits blue light to stimulate the material and measures the emitted luminescence with a photodetector or photomultiplier. The resulting signal is converted to an absorbed dose using calibration information, and most readers allow partial or complete signal erasure to reuse the device.

Advantages of OSL dosimeters include a wide detectable dose range, robustness to accidental light exposure, reusability, and the ability to store dose information for extended periods. Limitations include the need for specialized readout equipment, dependence of response on radiation energy and geometry, and fading or partial signal loss if not read promptly or properly reset.

OSL dosimeters are widely used for occupational dosimetry in medical, industrial, and research settings, as well as for retrospective dose assessments in certain environments. They provide a modern alternative to traditional thermoluminescent dosimeters with advantages in reusability and readout speed.