Chapter 2 X-ray and neutron digital radiography and computed tomography for cultural heritage

Abstract Methods of diagnosis based on digital radiography (DR) and computed tomography (CT), are more and more frequently used in the cultural heritage field. The application of these techniques can help restoration and conservation planners to understand historical construction techniques and to reveal poor restoration work and forgeries. As the size of objects of cultural interest varies greatly, from small fragments (for which high spatial resolution is needed) to large works of art (for which large detectors are necessary), it would not be appropriate to describe any one particular measuring device in detail. In this chapter, we will therefore provide an overview on Digital Radiography (DR) and Computed Tomography (CT) systems, underlining their range of applications. The chapter focuses mainly on X-ray radiation (with different kinds of sources) although neutron DR and CT are also mentioned, as neutron imaging should be considered complementary to X-ray imaging. Some DR and CT images, most of which were taken by researchers at the Department of Physics of the University of Bologna, are shown. This overview adopts a tutorial approach, as it is aimed at those with no specific knowledge of digital imaging. Three appendices have also been included (concerning Fourier transforms, modulation transfer function and DR and CT acquisition systems) for those readers who wish to acquire further skills in the field of digital imaging.