The denominator Dose rate of the age formula consists of two independent parameters, the internal dose rate and the external dose rate.Obviously, the denominator is crucial for the accurate determination of an age.Internal dose rate consists of three parameters related to the α, β and γ radiation, where the latter is usually small in most cases.
When a specimen is reheated, the trapped energy is released in the form of light (thermoluminescence) as the electrons escape.
The accuracy of the linearity in heating sample is crucial to have a precise measure.
The result of this measure is, as described above, a glow curve.
Heating ceramic in a furnace resets TL accumulated by clay and other materials; from this time on, TL begins growing again as time passes; the more concentrated radioactivity where ceramic is, the quicker TL grows.
Thus by measuring TL we can date an object since the last time it was heated above 400°C.