Identification Techniques II
An overview of applications of Small Angle X-ray Scattering (SAXS) techniques to topics of interest in the field of Cultural Heritage is presented. The basic concepts of the technique, a description of sources and laboratory instrumentation and some model
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Identification Techniques II Giovanni Ettore Gigante, Stefano Ridolfi, Michele A. Floriano, Eugenio Caponetti, Lorenzo Gontrani, Ruggero Caminiti, Maria Luisa Saladino, Delia Chillura Martino, Nick Schiavon, Cristina Dias Barrocas, Teresa Ferreira and K. Chrysafis
G. E. Gigante Department of SBAI, Sapienza University of Rome, Rome, Italy e-mail: [email protected] S. Ridolfi ArsMensurae, Rome, Italy M. A. Floriano E. Caponetti M. L. Saladino D. C. Martino Dipartimento di Chimica ‘‘S. Cannizzaro’’, Università degli Studi di Palermo, Parco d’Orleans II, Viale delle Scienze pad. 17, 90128 Palermo, Italy e-mail: [email protected] E. Caponetti (&) Centro Grandi Apparecchiature—UniNetLab, Università degli Studi di Palermo, Via F. Marini 14, 90128 Palermo, Italy L. Gontrani Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Area della Ricerca di Tor Vergata, Via del Fosso del Cavaliere, 100, 00133 Rome, Italy R. Caminiti Dipartimento di Chimica, Università di Roma, ‘La Sapienza’, P. le Aldo Moro 5, 00185 Rome, Italy N. Schiavon Evora Geophysics Centre and Hercules Laboratory for the Study and Conservation of Cultural Heritage, University of Evora, Largo Marqués do Marialva 8, 7000-809 Evora, Portugal e-mail: [email protected] C. D. Barrocas T. Ferreira Evora Chemistry Centre and Hercules Laboratory for the Study and Conservation of Cultural Heritage, University of Evora, Evora, Portugal K. Chrysafis Department of Physics, School of Science, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece e-mail: [email protected]
E. A. Varella (ed.), Conservation Science for the Cultural Heritage, Lecture Notes in Chemistry 79, DOI: 10.1007/978-3-642-30985-4_4, Springer-Verlag Berlin Heidelberg 2013
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4.1 X-Ray Techniques and X-Ray Fluorescence with Portable Systems Giovanni Ettore Gigante and Stefano Ridolfi
4.1.1 The Nature of X-Rays and Their Interactions The X-rays are very useful in the characterisation of works of arts for several reasons: • an excellent penetration in many materials constituting the artefacts; • basically simple interaction mechanisms that facilitate the development of techniques that have good specificity for some diagnostic tasks (such as X-ray fluorescence (XRF) for inorganic pigments); • sources and detectors that can be miniaturised to set up portable or mobile systems (if the X-rays’ intensities are low). The X-rays are an electromagnetic radiation with a very short wavelength (0.01–1 nm) produced in the interaction with targets of high energy charged particles (essentially electrons). They also can be produced in the de-excitation of inner shells of atoms (in this case they are monochromatic) and in the deviation of very high energy electrons beams as happens in the synchrotron radiation. The most important mechanisms of interaction of X-rays are: 1. photoionisation of atoms; 2. elastic and non-elastic scattering. The photoionisation is an interaction with inner electrons of atoms leading to the creation of a vacan
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