The Archaeometry Center is equipped (since 2008) with a TL/OSL Reader (Riso DA-20). Numerous of geological and archaeological interesting samples have been dated with the OSL dating method and the results are quite promising. The OSL dating method consists of the following steps:
Samples are chemically processed under red light (dark room conditions) and small portions of quartz, are extracted from the samples.
These quartz portions are measured for natural luminescence after optical stimulation and the equivalent dose of the sample is estimated (in Gy).
Soil that surrounds the measured samples are measured for natural radioactivity. Uranium, thorium, and potassium content is assessed and dose rate of the soil committed to the sample is calculated (in Gy/ka).
The age of the sample is calculated using the equation: Age = (Eq. Dose)/(Dose rate)
Usually, samples of soil from stromatographical beds at various sites with archaeological or geological interesting and ceramic shreds found at archaeological sites are dated.
The Archaeometry Center is performing TL measurements in flint-silex samples and pottery. The TL dating method outline is:
The 2mm outer part of the pottery or silex is discarded using a diamond saw. From the inner part, small portions are squeezed gently and powder in the range of 100-150 μm are collected and chemically processed.
About 5 mg aliquots are thermally stimulated up to 500o C and the glow curve of the natural luminescence N, is collected. Other aliquots are irradiated with known doses β, 2β, 3β... and measured for Ν+β, Ν+2β, Ν+3β...luminescence. All these glow curves are analysed and signals from a range of temperature (usally between 300o-450o C) are plotted against dose. Equivalent dose is estimated and the age of the sample is calculated using the same equation as above: Age = (Eq. Dose)/(Dose rate)