Thermoluminescence dating or TL dating is the dating of a material (such as quartz or field splash), based on measuring the amount of light released from that material due to thermal stimulation (thermoluminescence TL). Optical stimulation is also possible (optical stimulated luminescence or OSL). Principe
If the material in question has been in the sun or in a fire, latent luminescence in the material has disappeared substantially, thereby rendering the luminescent "clock" zero.
If the material is buried under sediments then luminescent potency increases by absorbing the natural background radiation caused by radioactive isotopes in the ground and some cosmic radiation. Crystalline structures become "excited", which stores the energy of the radiation. If the material is stimulated thermally (or optically) after excavation, the stored energy is released as a weak light. This light signal is a measure of the amount of radiation stored in the minerals. The age of the mineral is determined by dividing the total amount of stored radiation (the palaeodosis) by the annual amount of radiation stored. A reliable dating is possible from 100 years to 200,000 years, with a margin of error of 5 to 10%. After the release of this light, the luminescence clock is reset to zero. Therefore, thermoluminescence dating can only be performed once. Applications
Thermoluminescence dating is used for dating materials where carbon 14 dating is not possible. Thus, it is widely used to determine the age of old ceramic objects like vases. It gives about the date when the earthenware objects were baked in the fire.
Another application is to determine the age of wind deposits such as dunes or lice, which are protected by sunlight.
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