A comparative study of PIXE and XRF corrected by Gamma-Ray Transmission for the non-destructive characterization of a gilded roman railing

Several fragments of a gilded railing were found in the archaeological excavations carried out in Écija (Spain), among the remains of a collapsed temple. The alloy composition and the gilding procedure used for its manufacture are of interest for a complete archaeological knowledge of the artefact. The common use of IBA techniques directly on the objects for their analysis is not possible due to the thick corroded patinas that they exhibit due to the burial environment. However, non-destructive analyses of a few selected fragments have been done using PIXE and XRF techniques in combination with Gamma-Ray Transmission. Indeed, as was previously shown [1,2], bronze objects can be characterized in a completely non-destructive way using the combination of these techniques. This work, shows the applicability of that method to artefacts made of leaded copper alloy, which is the case of samples studied, for which some problems could arise from the lead segregations present in these kind of alloys. We have found that this railing contains low amounts of Sn and Sb, and that the gilding was most probably obtained using a gold leaf.