|Particle accelerators for the study of Cultural Heritage (Vol. 42, No. 3)|
Details of the painting by Mantegna (above, part of the veil of the Virgin; below, the eye of the Virgin), and corresponding X ray distribution maps obtained by PIXE at the external scanning micro-beam set-up at INFN-LABEC.
This paper is a first critical discussion of the contemporary role that small particle accelerators play in the field of applications related to Cultural Heritage for non-destructive materials analysis and dating, such as ion beam analysis (IBA) and accelerator mass spectroscopy (AMS). This analysis is put in perspective by comparing accelerator-based methods to other techniques, pointing out the corresponding pros and cons. It is stressed that IBA can address questions that cannot be answered by conventional techniques like X-ray fluorescence (the latter having however the advantage of portability). It is shown in particular that IBA can still yield unrivalled results thanks to novel uses of its potential, such as providing elementalmaps and resolving layer structures. This was strikingly demonstrated in a recent PIXE (Particle Induced X-ray Emission) analysis at LABEC of Mantegna’s famous painting Madonna con Bambino (see figure), which used the scanning external proton microbeam set-up to produce a high-resolution elementalmapping.The use of different, even precious, pigments to paint tiny details is thus pointed out, which can be of great interest to art historians and restorers. In addition, by utilizing the different absorption rates of different X-ray energies, even the paint layer structure can sometimes be reconstructed: for example, in the case shown in the upper part of the figure, it is shown that the Virgin’s veil was made with a gold paint over a background of ultramarine blue, lightened with lead-white. No other technique can provide such information in a totally non-destructive way and with no pick-up of samples
The present role of small particle accelerators for the study of Cultural Heritage