OSL dosimeters record dose by storing energy in luminescent centers and releasing it as light when stimulated. Which statement best describes this mechanism?

• A. They release energy as heat when heated
• B. They store energy in trapped electrons and release it via stimulation with light
• C. They emit visible light continuously regardless of stimulation
• D. They require magnetic fields to read dose

Answer: (B)

OSL dosimeters store energy in trapped electrons within luminescent centers when they’re exposed to ionizing radiation. Later, light stimulation frees those trapped electrons, they recombine at luminescent centers, and the material emits photons. The brightness of that emitted light is proportional to how much charge was trapped, which reflects the absorbed dose. This optical readout distinguishes OSL from thermoluminescent dosimetry, where heating releases the stored energy as light, and from methods that require magnetic fields, since the readout here uses light stimulation and detection rather than heat or magnetism.