What active material is used in the construction of a Thermoluminescent Dosimeter (TLD)?

Thermoluminescent Dosimeters (TLDs) primarily utilize lithium fluoride as the active material due to its favorable properties for measuring ionizing radiation. Lithium fluoride is effective because it has a high atomic number, which allows it to interact more effectively with radiation and accumulate a measurable amount of energy within its crystalline structure.

When TLDs are exposed to radiation, lithium fluoride can trap electrons in its lattice structure. Upon heating, these trapped electrons are released, and as they recombine with holes in the lattice, they emit light. The intensity of this light is proportional to the amount of radiation exposure, making TLDs highly effective for dosimetry purposes.

This characteristic makes lithium fluoride particularly suitable for applications requiring precise measurements of radiation exposure over time, such as in medical environments or radiation safety monitoring in various industries. Other materials listed, while they have their own uses in different types of detectors or dosimetery, do not match the effectiveness of lithium fluoride in TLD applications.