Thermoluminescent dosimeters (TLDs) are devices used to measure ionizing radiation exposure. They contain materials that store energy from radiation, which can later be released as light when heated. This light is then measured to determine the amount of radiation the TLD has absorbed. TLDs are commonly used in various fields, including medical applications, nuclear power plants, and research laboratories. They provide a reliable way to monitor radiation levels and ensure safety for workers and the public. Their ability to provide accurate readings over time makes them valuable tools in radiation protection.