XRF technique

The techniques of chemical investigation by X-ray fluorescence (XRF) are widespread since the 50s of the last century. Depending on the accuracy of the desired data and on the artifact characteristics, they can be used as partially destructive or as absolutely non-destructive and non-invasive techniques. The archeomaterials that can be analyzed are the most disparate: minerals, rocks, metals, building materials, pigments, and so on; practically almost everything that is solid, liquid or gelatinous can be analyzed by XRF. The theoretical physical principles and the main components of X-ray spectrometers, in energy dispersion (ED) and wavelength dispersion (WD), are described, also comparing the advantages and disadvantages of each analytical technique. In the last decades, the diffusion of the ED silicon drift detectors, together with the development of very accurate and high specialized software for quantitative analysis, has given a new impulse to the diffusion of the portable spectrometers offering new possibilities for in situ and very rapid archeomaterial characterizations. Case studies related to different artworks, like ceramics, necklaces, coins, obsidians and other lithic artifacts will also be presented: they show the important contribution that X-ray spectrometer technique gives to solve problems related to the characterization, restoration and to the source identification of the raw materials.