Thermoluminescence is the emission of light from a material when it is heated, following previous exposure to ionizing radiation.
- Exposure to Radiation: When a material (usually a crystalline solid) is exposed to ionizing radiation (like X-rays, gamma rays, or cosmic rays), some electrons within the material get trapped in imperfections within the crystal structure.
- Heating and Light Emission: When the material is heated, these trapped electrons gain enough energy to escape their traps. As they return to their original energy state, they release energy in the form of visible light.