Which type of personnel dosimeter contains a crystalline form of lithium fluoride?

Thermoluminescent dosimeters (TLDs) are indeed the type of personnel dosimeter that contains crystalline forms of lithium fluoride (LiF). The lithium fluoride crystals serve as the active sensing material in TLDs, where they absorb and store energy from ionizing radiation. When the crystals are heated, they release this stored energy in the form of light, which can be measured to determine the amount of radiation exposure.

The use of lithium fluoride is significant because it closely resembles human tissue in terms of its radiation interaction characteristics, providing an accurate representation of the dose received by the wearer. TLDs are widely used in various radiation monitoring applications due to their sensitivity, range of measurable doses, and the reusability of the dosimeters after they have been read out.

This understanding highlights how TLDs are distinct in their operation compared to other dosimeter types, which use different materials and principles for measuring radiation exposure.