Definition of luminescence dating
They lose their power of luminescence during the day and only regain it at dusk or when kept in the dark for some time.
Radziszewski himself and many other authors have compared the light of organisms to this type of luminescence.
The amount of light produced is a specific and measurable phenomenon.
Material and objects of archaeological or historical interest that can be dated by thermoluminescence analysis are ceramics, brick, hearths, fire pits, kiln and smelter walls, heat treated flint or other heat-processed materials, the residues of industrial activity such as slag, incidentally fire-cracked rocks, and even originally unfired materials such adobe and daub if they had been heated in an accidental fire.
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.
Apparently there is no rhyme or reason in the distribution of luminescence throughout the plant or animal kingdom.
The distinction between light and luminescence was first pointed out by Wiedemann .
Subsequent heating of the crystal can release some of these trapped electrons with an associated emission of light.
Since measured TL depends on time of exposition to natural radiations but also on the intensity of these radiations, to achieve a precise dating we need information about radioactivity of the area where the object was found.
During TL analysis, the sample is reheated by a controlled heating process, so the energy is released in the form of light (thermoluminescence) as the electrons escape.
The paleodose is the absorbed dose of natural radiation accumulate by a sample.
This paleodose is determined from the TL signal measured by heating sample at a constant rate.