Chapter 12: Evolution of Portable Devices: Using EDXRF to Study Works of Art

This chapter describes the history and technical evolution of portable devices which use energy-dispersive X-ray fluorescence (EDXRF) analysis to study pigments in paintings and elemental compositions of ancient metals. The history starts in 1971 when the first transportable equipment was employed to examine the pigments of Raphael's painting “La Deposizione” during restoration at the Istituto Centrale del Restauro in Rome. Subsequent paintings were analyzed, as well as ancient metals such as bronzes, brasses, gold, and silver. This chapter traces the evolution of the excitation source from radioisotopes to miniaturized, dedicated X-ray tubes, X-ray detectors, from proportional gas counters to Peltier cooled Si-drift, and the developments of pulse height analyzers, from a heavy box to miniaturized electronic circuits included in the detector box. The most “modern” portable EDXRF device is currently composed of a small sized X-ray tube, a Si-drift detector, both properly collimated, and a dedicated PC. The total weight of the device is about 2 kg. Finally, we explore these evolutions in portable XRF devices from the perspective of the analysis of a limited number of points on each work of art through to a complete scanning of a painting. Sophisticated software is required including interfacing mechanics and measuring heads. Maps showing the elemental distribution in the painting “La Fornarina” by Raphael have been obtained using this method.