Determination of chemical homogeneity of historical glassware using autoradiography of potassium natural radioactivity

There is a range of elements with a radioactive long-life isotope. That iso tope is often the component of a naturally existing element. Autoradiograph y is one of the methods allowing us to detect natural radioactivity of elem ents. Using autoradiography, we can carry out non-destructive and non-sampl ing investigations of the historical glassware. The main purpose of such work was to determine the potassium content in the tested glassware as well as to determine the chemical homogeneity of the o bject. The natural radioactivity of the isotope K-40 has been used here. The broken stem of an 18th century goblet, made of colourless, high quality glass has been analysed. Our experiment consisted of two parts: examinatio n of model glasses with calibration of the method and examination of broken stem. Obtained results showed us large inhomogeneity of the old glass. Dif ferences in K2O concentration were in the range of 13-20%. It means that ch emical inhomogeneity of historic glasses cannot be omitted during investiga tions that require sampling. (C) 2001 Elsevier Science Ltd. All rights rese rved.