The complementary use of PIXE- and XRD non-destructive portable systems for the quantitative analysis of painted surfaces

This work presents the results of a non-destructive analysis carried out using the portable PIXE-alpha (particle-induced X-ray emission) system developed in collaboration by the INFN/LANDIS (Catania, Italy), the CNR/IBAM (Catania, Italy) and the CEA/LIST (Saclay, France), and the portable XRD (x-ray diffraction) diffractometer recently upgraded at the INFN/LANDIS. It is shown that using a combination of the two techniques, quantitative analysis is possible in some cases. The results of its application to Roman fresco fragments obtained from different archaeological sites in Catania (Italy) are presented. These results make it possible to identify the quantitative presence of various pigments: coloured earths, ochre, hematite, goethite, cinnabar, and Egyptian blue have been identified and quantified.