Rapid, quantitative, and non-destructive SR-WD-XRF mapping of trace platinum in Byzantine Roman Empire gold coins

Abstract

Non-destructive analytical techniques that enable the rapid screening of large numbers of coins are of interest for numismatic studies. Using a tuneable synchrotron X-ray source provides an intensity that cannot be matched by laboratory X-ray fluorescence (XRF) sources, reduces analytical time and increases sample throughput. Here we evaluate the combination of the high intensity and spatial resolution provided by a synchrotron source with the highly resolved sensitivity afforded by a wavelength dispersive (WD) spectrometer for the rapid, quantitative, and non-destructive XRF mapping of trace platinum in ancient Roman gold coins. In this study, the rapid mapping of >3300 data points in (400 μm × 400 μm) areas was done to determine Pt distribution across the gold coin matrix. Quantitative analysis was performed by using gold reference materials with known platinum concentrations. The results of this study agree within −11 to +3% of previously determined trace platinum concentrations in these gold coins. The application of this method will enable researchers to quickly screen large numbers of ancient coins for classification and comparison for further analysis.