What is the primary purpose of a TLD in personal monitoring?

A thermoluminescent dosimeter (TLD) is specifically designed to provide a permanent record of an individual's radiation exposure. The fundamental principle behind a TLD is that it contains crystalline materials that absorb energy from ionizing radiation. When the TLD is heated, it releases this stored energy in the form of light, which can then be measured to quantify the dose of radiation that the individual has been exposed to over time.

This characteristic makes TLDs particularly valuable in environments where long-term monitoring is required, as they can retain exposure information for extended periods. The ability to record cumulative doses means they serve as a reliable archive of exposure history, which is essential for ensuring the safety of radiation workers and for regulatory compliance.

In contrast, while measuring environmental radiation levels, providing real-time readings, or indicating radiation types can be important in various contexts, these are not primary functions of a TLD. TLDs do not provide instantaneous exposure data and do not differentiate between types of radiation; rather, their primary role lies in reporting accumulated doses for future reference and assessment.