Sample discs are mounted on a wheel and the readers are programmed to run heating and irradiation sequences.The TL is measured using a sensitive detector called a photomultiplier tube.
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.
The older the pottery, the more radiation it has absorbed and the brighter the pottery sample glows.
By measuring the TL, we can calculate how much radiation has been absorbed and use this information to calculate the approximate age of the pottery.
The amount of light produced is a specific and measurable phenomenon.
If the specimen’s sensitivity to ionizing radiation is known, as is the annual influx of radiation experienced by the specimen, the released thermoluminescence can be translated into a specific amount of time since the formation of the crystal structure.
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.
Any remaining powder is dried and used for radioactivity measurements to complete the dating calculation. When the glue is dry, they are cut into slices 1/4mm thick with a fine diamond blade. Each slice is soaked in acetone after cutting to remove the glue. The remaining core is crushed and used for radioactive analysis to complete the dating calculation.
We have 3 fully automated, computer operated Riso Minisys TL readers for measuring the TL.
When a small sample of ancient pottery is heated it glows with a faint blue light, known as thermoluminescence or TL.