K-edge Radiography and applications to Cultural Heritage

Abstract

The present work of thesis is focused on application of X-ray K-edge technique to paintings. This technique allows one to achieve a topographic map of a pigment on the whole surface of the painting. The digital acquisition of radiographic images by using monochromatic X-ray beams allows to take advantage of the sharp rise of X-ray absorption coefficient of the elements, the K-edge discontinuity. Working at different energies, bracketing the K-edge peak, allows recognition of the target element. The K-edge radiography facility installed at Larix Laboratory, at Department of Physics in Ferrara, consists of a quasi-monochromatic X-ray beam obtained via Bragg diffraction on a mosaic crystal from standard X-ray source. In this work the K-edge technique and the facility used are illustrated. A characterization of the monochromatic beams in the energy range 7-40 KeV range and the elemental mapping on pictorial layers obtained are presented. At the end, a transportable facility for digital radiography is presented and some radiographic analysis of works of art performed are shown