Which of the following is a type of thermoluminescent dosimeter?

A thermoluminescent dosimeter (TLD) is a device used to measure ionizing radiation exposure by storing energy from radiation in a crystal lattice. When heated, these crystals release the stored energy in the form of visible light, which can be measured to quantify the amount of radiation exposure.

The ring dosimeter, specifically designed to be worn on the finger, uses thermoluminescent materials to measure radiation exposure effectively. This type of dosimeter is commonly used by radiology professionals who may be exposed to radiation during their work, allowing for precise monitoring of exposure over time.

In contrast, the other options represent different types of dosimeters that operate on alternative principles. An optically stimulated luminescence dosimeter utilizes light stimulation rather than heat to release stored energy. A film badge integrates photographic film to detect exposure by changing its density, while a pocket ionization chamber provides a direct reading of radiation exposure through ionization effects. Therefore, these alternatives do not fall into the category of thermoluminescent dosimeters like the ring dosimeter does.