Analysis of ancient embroideries by IBA techniques

摘要

Ion beam analysis (IBA) techniques are often used to study works of art, mainly for their nondestructive character. In these techniques, products of interactions between beams and targets are exploited to determine the elemental composition of the sample surface down to depths from few micrometres to hundreds of micrometres, depending on incident particles, their energy and target material. For samples with surface inhomogeneities, information about elemental distribution can be essential to discriminate contributions from different areas. At the authors' laboratory in Florence (LABEC), the external scanning proton microprobe facility - installed on a beam line of the 3 MV Tandem Accelerator - allows samples to be analysed in atmosphere, with spatial resolution down to around micrometres, and to extract elemental maps from the investigated areas. Recently, there has been the opportunity of analysing a 'gold lace embroidery' (using silk threads, spiral wrapped by a sort of miniature golden tape) after a cartoon by Raffaellino del Garbo (the fifteenth-sixteenth centuries).