Metrological characterization and implementation of innovative X-Rays imaging instruments and techniques: digital radiography and tomography and the application in the Cultural Heritage field.

The aim of this research project is the characterization from a metrological point of view of innovative instruments for imaging based on X-rays. The characteristics evaluation of measuring instruments is of fundamental importance in the field of scientific research: in order to define their performance, it is necessary to analyze the limits and inaccuracies of instruments, obtaining all the information for the correct use and allowing the user to obtain the best results in all the possible conditions

The characterization work is focused in particular on an innovative instrumentation supplied by the Physics Department and installed in the NIS laboratories (Nanostructured Interfaces and Surface) of the University of Torino. It consists of a new X-ray source, called Metal-Jet, of the Swedish company Excillum, and a flat-panel detector from Varex Imaging, both purchased in the framework of the SAX-Infra-P(PORFESR) project.

The MetalJet source is part of a new generation of instruments, based on an innovative liquid anode technology that allows to obtain a higher brightness compared to the solid anode sources (10x), despite the micrometric range of the focal spot size (5-40 μm) achievable, helping the scientists to perform research and analysis previously not possible outside the Synchrotron facilities. This entire set-up is aimed at carrying out radiographic and CT analysis and their application to archaeological finds and historical-artistic objects of interest, which is one of the main research lines of the group. Digital X-Ray Imaging tecniques are based on the different x-rays absorption of samples, due both to different thickness of the same material or to the presence of some materials with different absorption coefficient, and the obtainable results are digital grey scale images, in 2D for radiography and 3D for tomography. These techniques are widely used in the field of Cultural Heritage above all thanks to their non-invasiveness; the high penetrating power of X-rays allows us to investigate the internal structure of the analysed objects obtaining valuable information about the nature of constituent materials, alterations and state of preservation, hidden features, constructive techniques and previous restoration. All this information increases the knowledge about an artwork or an archaeological findand can be useful for art-historians, archaeologists and restorers.

In particular, CT provides data that are more significant when objects with a not negligible volume are studied. Even the use of advanced instruments can help having better final data from which getting more information, that is one of the goal of this project.

In the figures are shown respectively: the MetalJet X-ray source, the X-ray imaging set-up at the NIS centre and a portion of the DR and CT scan of an Egyptian wooden coffin realized at the CCR centre of Venaria Reale using another apparatus [Re 2016].


[Re 2016] A. Re, et al., "The importance of tomography studyng wooden artefacts: a comparison with radiography in the case of a coffin lid from Ancient Egypt", International Journal of Conservation Science 7(SI2): 935-944 (2016)