6.5 Cultural Heritage: Artefacts and Materials

The discovery of ancient artefacts and artworks that bear witness to our cultural heritage typically raises a variety of questions: from the correct determination of their historical and cultural time-frame, the location and method of production, to the choice of treatments and environmental conditions for restoration and preservation. A large variety of chemical, physical and microstructural techniques are currently employed to characterise objects of cultural significance, indeed the same techniques that are generally applied to studies in the mineralogical and material sciences, and which deal with the characterisation of solid, generally inorganic matter such as; mineral, stone, ceramic, glass, metal, and their derivates. Neutrons, as opposed to x-rays, are the best probe for examining the interior of thick samples. Neutron analysis, which is intrinsically non-invasive, is both unique and complementary to more conventional techniques. When sampling is not possible, neutron methods provide chemical, phase specific, and microstructural information from undisturbed large volumes. Furthermore, comparison with artificially produced materials, such as metals and alloys, can also be effectively exploited in order to obtain indirect information on the manufacturing techniques of the objects under investigation. Specifically, TOF neutron diffraction at the ESS will provide invaluable information on objects from museums and galleries that must not be damaged by cutting, drilling, scraping etc. Data can be collected from large, intact objects of almost any shape, and the experimental set-up is both simple and free from sample movements. The many-fold increment in signal and resolution afforded by this new source, will allow element sensitive small volume phase identification and quantification, detailed crystal structure analysis of the constituent phases, and direct imaging in two- three- and four- (diffraction) dimensions by imaging and tomography making use of energytuning techniques. These methods could certainly provide a clearer picture of the technological, commercial and, more generally, historical and archaeological aspects of the sample. With a view towards preservation, they would provide invaluable information regarding the choice of restoration and conservation procedures. As with the mineral and Earth sciences, the potential of neutron scattering is only recently being realised in the fields of preservation of cultural heritage and archaeometry. With the availability of an ESS-class neutron source there is much to look forward to with the opening of new avenues in this field of study.