NUCLEAR PHYSICS METHODS IN CULTURAL HERITAGE RESEARCH - ACCELERATORS FOR ART

A review will be given on the use of nuclear physics techniques in non-destructive investigations on our cultural heritage objects. It focuses on making use of the production and detection of X-rays as a tool for micro analysis. At 'small accelerators', a versatile approach to determine elemental compositions as major constituents or as trace elements is the proton induced X-ray emission (PIXE), especially when combined with Rutherford backscattering spectroscopy (RBS), a powerful technique for near-surface investigations with micrometer resolution, and nowadays, with the use of improved detection sensitivities, set up for elemental mapping of large areas in a reasonable time for data taking. Such 'small accelerator' installations are well complemented by larger facilities, synchrotron radiation sources as well as medium energy ion accelerators for high energy PIXE. When high energy protons are used as inducing particles with energies between about 20 and 100 MeV - elements deeply buried under several hundreds of micrometer of corrosion layers, can easily be identified, too. These techniques are complemented by X-ray fluorescence, which have recently been developed into a 3-dimensional micro analytical technique with a resolution of around 30 micrometers by employing multi capillary X-ray guiding lenses. The state-of-the-art methodology will be illustrated on examples from painted glass windows and luster ceramics closely related to basic research on nanometer sized metallic inclusions in glasses for plasmonics in photonics. Finally, an outlook will be given for a new generation under way of almost mono-energetic high-energy and high-intensity X-ray sources being developed as 'table-top' instrumentation with MeV-electron LINACS rather than GeV-electron synchrotrons.