Thermoluminescence studies of a Gothic church in Świebodzin from Silesia in Poland

Abstract

The paper presents thermoluminescence (TL) studies that aim to establish the possibility of using such analysis to determine the date of the construction, transformation and/or rebuilding of a historical church. The determination of the age of building structures using the form of absolute dating that is now used by architects and archeologists is difficult and complex. A relatively large error of estimation can be observed in archeological studies. In the case of samples from the Middle Ages, such errors are not acceptable. The authors attempted to develop an alternative spectroscopic TL method for such studies, and proposed that the composition of bricks should be measured using X-ray diffraction, electron microscopy (EM) and TL spectra. The bricks for the testing were taken from internal walls and the walls in the attics of churches, i.e. from places built during the last stage of construction works. The TL measurements were made using x-ray and β source excitation within the temperature range of 25–500°C. Two different sizes of grains were studied: small (∼0.1 mm) and large (∼0.5 mm). A gothic church in Świebodzin from 1555, which has a well-known history of its construction, was selected for the investigations. Due to the fact that this church is 326 years younger than the two churches evaluated and described in [1], the composition of its bricks could be different. Therefore, the authors decided to compare the XRD data, EM results and TL spectra for bricks taken from all three churches. The intensities of the TL and the integrated TL intensities were determined. The measurement results are important for creating a relationship between the TL intensity and the date a building object was constructed. Moreover, thanks to this it was possible to verify the construction date of Saski Palace in Warsaw.