Dating romance in tl
Most excited electrons will soon recombine with lattice ions, but some will be trapped, storing part of the energy of the radiation in the form of trapped electric charge (Figure 1).
Depending on the depth of the traps (the energy required to free an electron from them) the storage time of trapped electrons will vary as some traps are sufficiently deep to store charge for hundreds of thousands of years.
The sample material is illuminated with a very bright source of green or blue light (for quartz) or infrared light (for potassium feldspars).
Ultraviolet light emitted by the sample is detected for measurement.
Ideally this is assessed by measurements made at the precise findspot over a long period.
For artworks, it may be sufficient to confirm whether a piece is broadly ancient or modern (that is, authentic or a fake), and this may be possible even if a precise date cannot be estimated.
An example of this can be seen in Rink and Bartoll, 2005.It will often work well with stones that have been heated by fire.The clay core of bronze sculptures made by lost wax casting can also be tested.Different materials vary considerably in their suitability for the technique, depending on several factors.Subsequent irradiation, for example if an x-ray is taken, can affect accuracy, as will the "annual dose" of radiation a buried object has received from the surrounding soil.