Analysis of cultural heritage reference materials by portable and energy dispersive X-ray fluorescence measuring methods: results reliability assessment

This article discusses the results of a large-scale analysis of five cultural heritage alloy reference materials (CHARM) and their shavings using handheld (pXRF) and stationary energy dispersive (ED-XRF) spectrometers. The primary objective of these studies was to assess the capability of the pXRF and ED-XRF spectrometers as a non-invasive surface-measuring technique used for the analysis of the reference materials and the reliability of the data obtained. The second objective was to evaluate the capability of the pXRF and ED-XRF spectrometers used for the analysis of shavings of the same five reference materials and to assess the data obtained. These objectives required finding the best fitting analytical tools for the comparison, and the assessment of the reliability of the data, and, very importantly, finding reliable models for data analysis and results validity verification. Based on the analysis carried out on the cultural heritage alloy reference materials, it can be concluded that the results of XRF spectrometry obtained from both spectrometers are reliable and can be compared to each other by making reference to four basic conditions: that the provided analysis should be based on certified reference materials of known elemental composition; that analysis be performed according to appropriate measuring methodology (research protocol); that analysing tools (predictive analytics) be clearly defined; and, finally, that testing be done on archaeological artefacts. The reliability and inter-correlation of the results obtained were assessed to determine the possibility of successfully applying XRF spectrometry in the investigation of archaeological artefacts produced from copper alloys.