Micro-PIXE Analysis of Ancient Roman Coins

This work is part of a wider project concerning the characterization of ancient Roman Republican coins and contemporary Celtic coins from northern Italy. In order to understand which technique could provide data useful for numismatic studies, a multi-techniques approach was used at the beginning of the project. Some coins have been sectioned to study their microstructure and especially to assess the presence or absence of corrosion layers, enriched layers and non-homogeneities between surface and bulk. Actually, the presence of a surface silver- enriched layer (from few μm up to hundreds μm) is quite common in objects made of a silver-copper alloy, and some papers in literature have already faced and discussed the topic. Measurements presented here have been useful to understand the microstructure of the coins under analysis and helped to plan consciously further analyses.