The new version of the portable XRD system of the LANDIS laboratory and its application for the non-destructive characterisation of pigments in ancient Roman frescoes

A new version of the portable XRD (X-Ray Diffraction) system of the LANDIS laboratory of Catania is presented. The previous apparatus, a commercial portable diffractometer, was equipped with a new X-ray source realised by using a low-power microfocus tube coupled to a polycapillary semi-lens optics. The new experimental set-up allowed to improve the angular resolution and to increase the intensity of peaks in the diffractograms with respect to those measured with the previous version of the system. Finally, the application of the diffractometer for the non-destructive characterisation of pigments present in some fragments of ancient Roman frescoes is discussed.