What chemical is used in dosimeters?

• A. Lithium fluoride
• B. Potassium iodide
• C. Aluminum oxide
• D. Sodium fluoride

Answer: (A)

Lithium fluoride is the material most commonly used in dosimeters because it stores and later releases energy as light in a way that closely reflects the absorbed radiation dose. When irradiated, LiF crystals trap energy; heating then liberates trapped electrons, producing light proportional to the dose. This material is favored because its response is well characterized, it can be doped (for example LiF:Mg,Ti, known as TLD-100) to give a stable, linear dose response over a wide range, and its atomic composition is close to that of human tissue, making readings more representative of actual biological dose.

Potassium iodide isn’t used as a dosimeter material; it’s more often involved in thyroid protection or imaging contexts. Aluminum oxide is used in a different dosimetry technology (optically stimulated luminescence), not the traditional thermoluminescent approach. Sodium fluoride can be used in some dosimetry formulations, but lithium fluoride remains the standard choice because of its tissue equivalence and well-established calibration.