Which statement correctly describes how TLD and OSL dosimeters read dose?

• A. TLD reads by heating to release trapped electrons; OSL reads by optical stimulation.
• B. OSL reads by heating; TLD reads by optical stimulation.
• C. Both read by heating.
• D. Both read by optical stimulation.

Answer: (A)

Reading dose in these dosimeters hinges on how stored radiation energy is released. In a thermoluminescent dosimeter, heating provides enough energy to release trapped electrons; as they recombine, they emit light that the reader measures, with the light amount proportional to the dose. In an optically stimulated luminescence dosimeter, light instead stimulates the traps to release electrons, which then recombine and emit light that is measured. Therefore, this description—TLD readout by heating and OSL readout by optical stimulation—is the correct one.