Non-destructive measurements on roman pottery. International workshop on Old pottery in a new century. Innovating perspectives on Roman pottery studies

In the present work the portable PIXE-alpha system and the portable BSC-XRF spectrometer (Beam Stability Controlled-XRF), realised at the LNS/INFN laboratories of Catania in collaboration with the Italian CNR, have been used for the non-destructive analysis of some Roman pottery artefacts of different typologies. The PIXE-alpha method has been used to quantitatively characterise the artefacts glazes; the PIXE investigation is in fact limited to the thin surface layer (less than 10 ?m) and any contribution of the ceramic body is not present in the PIXE experimental data. The XRF techniques has been used for the quantitative determination of some trace elements (Rb, Sr, Y, Zr and Nb) of interest in provenance studies. Analysis has been performed by using a multi-linear regression approach developed at the LNS/INFN laboratories. It could be observed that the XRF analysis is limited to the near surface layer (less than 100 ?m) and a quantitative determination is meaningful only when the material being analysed is homogenous. In order to test the homogeneity of the material composing the analysed samples, a small portion (less than 1 gram) of the artefacts has been powdered, carefully homogenised and pressed to a disk-shaped pellet. The powdered pellets have been measured and quantitatively analysed. A comparison between the non destructive and the destructive data is presented and discussed. Finally, the trace elements composition has been used to classify the artefacts in typological classes by performing a multivariate cluster analysis.