Luminescence dating method reformed theology dating
The phenomenon of thermoluminescence was first described by the English chemist Robert Boyle in 1663.It was employed in the 1950's as a method for radiation dose measurement, and soon was proposed for archaeological dating.It is also rare that any information about the radiation from the burial soil can be obtained, as art objects are usually thoroughly cleaned.This radiation may in some cases contribute over half the total dose. 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). It is an absolute dating method, and does not depend on comparison with similar objects (as does obsidian hydration dating, for example).
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In all, close to two dozen physical quantities must be accurately measured to establish the relationship between doses of different kinds of radiation and light output, and to compute dose rate.
A leaflet from Daybreak describing the TL technique in more detail and giving a bibliography will be provided to interested persons.
In some categories of objects, from China, for example, the actual age is quite precisely known for short-lived styles, and it is possible to work "backwards" to get information about the environment in many parts of the world, and some other parameters not usually measurable for art objects.
Using this information often reduces the uncertainty to 15-25 per cent. Nearly any mineral material which has been heated above 500C at a time one wishes to know is a candidate for TL dating. Porcelains, being nearly vitrified, are a special case requiring a fairly large solid core sample, and TL dating of intact objects is not recommended because of the damage caused by sampling.