What is thermoluminescence dating used for

By comparing this light output with that produced by known doses of radiation, the amount of radiation absorbed by the material may be found.

Most mineral materials, including the constituents of pottery, have the property of thermoluminescence (TL), where part of the energy from radioactive decay in and around the mineral is stored (in the form of trapped electrons) and later released as light upon strong heating (as the electrons are detrapped and combine with lattice ions).

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Prior to the final depositional episode it is necessary that any previously acquired TL is removed by exposure to sunlight.

After burial the TL begins to build up again at a rate dependent upon the radiation flux delivered by long-lived isotopes of uranium, thorium and potassium.

Warning about fakes using ancient materials What about airport x-rays and radiography? Thus, when one measures dose in pottery, it is the dose accumulated since it was fired, unless there was a subsequent reheating.

When pottery is fired, it loses all its previously acquired TL, and on cooling the TL begins again to build up.

This energy is lodged in the imperfect lattices of the mineral's crystals.

Heating these crystals (such as when a pottery vessel is fired or when rocks are heated) empties the stored energy, after which time the mineral begins absorbing energy again.

Two forms of luminescence dating are used by archaeologists to date events in the past: thermoluminescence (TL) or thermally stimulated luminescence (TSL), which measures energy emitted after an object has been exposed to temperatures between 400 and 500°C; and optically stimulated luminescence (OSL), which measures energy emitted after an object has been exposed to daylight.

To put it simply, certain minerals (quartz, feldspar, and calcite), store energy from the sun at a known rate.

It is an absolute dating method, and does not depend on comparison with similar objects (as does obsidian hydration dating, for example).

The thermoluminescence technique is the only physical means of determining the absolute age of pottery presently available.

When we receive your sample we must first prepare it for measurement.

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