Evaluation for the paleodose in thermoluminescence dating of porcelain

Abstract

Sources, components and calibration of paleodose were studied for proper evaluation of the paleodose of porcelain in thermoluminescence (TL) dating. In the TL dating of porcelain using the pre-dose technique, the β dose from the internal natural radiation in the body of porcelain is the first, the environmental dose the second, and the α dose negligible. Sample thickness of 0.2–0.5 mm was used in the paleodose calibration. For a porcelain sample of such thickness, the distribution of β dose inside the sample was nonlinear when the sample (aluminium replaces porcelain in this experiment) was irradiated by a laboratory ⁹⁰Sr-⁹⁰Y β source. Therefore, the β dose used was only an average value. A distribution curve of β dose and the calculation of average β dose in the sample were obtained, according to the build-up and attenuation effects of β dose in the sample. The results showed that a sample thickness of 200 μm resulted in an average dose increment of about 4% compared to the surface whereas for a sample with a thickness of 400 μm, the average dose reduced by the same percentage, and that for a sample of 300 μm in thickness the average dose is equal to surface dose approximately. The average β dose in samples with various thickness can be obtained by the provided equations.