What is the sensing material in Thermoluminescent Dosimeters (TLDs)?

• A. Calcium sulfate
• B. Silicon dioxide
• C. Lithium fluoride
• D. Gallium nitride

Answer: (C)

Thermoluminescent Dosimeters (TLDs) are designed to measure ionizing radiation exposure by utilizing specific materials that exhibit thermoluminescence properties. The sensing material in TLDs is Lithium fluoride (LiF). When exposed to radiation, lithium fluoride absorbs energy, which causes electrons to be trapped at defects in the crystal structure.

Upon heating the TLD, these trapped electrons are released, and they emit light in the process, which is proportional to the amount of radiation the detector has been exposed to. This characteristic makes Lithium fluoride highly effective for use in TLDs, as it enables the accurate measurement of radiation doses. The other materials mentioned, while they may have other applications in radiation detection or semiconductor technology, do not possess the specific thermoluminescent properties that make Lithium fluoride the optimal choice for TLDs.