If, however, the temperature of the phosphor is progressively raised, electrons will receive increasing amounts of thermal energy and will have an increased probability of escape from the traps.Freed electrons may then go over to luminescent centers and recombine with holes trapped at or near these centers.A particular isotope of a particular element is called a nuclide. That is, at some point in time, an atom of such a nuclide will spontaneously change into a different nuclide by radioactive decay.The decay may happen by emission of particles (usually electrons (beta decay), positrons or alpha particles) or by spontaneous nuclear fission, and electron capture.Contamination from outside, or the loss of isotopes at any time from the rock's original formation, would change the result.It is therefore essential to have as much information as possible about the material being dated and to check for possible signs of alteration.
See Hole states in solids, Traps in solids Radiation dosimeters based on thermoluminescence are widely used for monitoring integrated radiation exposure in nuclear power plants, hospitals, and other installations where high-energy radiations are likely to be encountered.
Different dating methods may be needed to confirm the age of a sample.
For example, a study of the Amitsoq gneisses from western Greenland used five different radiometric dating methods to examine twelve samples and got agreement to within 30 million years on an age of 3,640my.
Thermoluminescence can be observed in many crystal phosphors and minerals and in several glasses and organic phosphors.
The mechanism of thermoluminescence involves recombination. Upon heating, trapped electrons are liberated, and they re-combine with luminescent centers that were ionized upon excitation, producing radiation.
Radiometric dating is also used to date archaeological materials, including ancient artifacts.