27 April 2023
Photo: Marta Mayer/DESY
In two pilot studies, scientists from Hamburg investigate historical written artefacts at the X-ray radiation source PETRA III. The experiments revolve around Mesopotamian clay tablets and Tibetan artefacts belonging to the Bon tradition.
Precise analyses of the origin and age of written artefacts form the foundation on which historical contexts can be reconstructed. Since the market for looted goods and forgeries is flourishing, these analyses are becoming increasingly important. For this reason, research on written artefacts now frequently employs approaches in the natural sciences and material science. Within a new cooperation between the Cluster of Excellence ‘Understanding Written Artefacts’ (UWA) at Universität Hamburg and the German Electron Synchrotron DESY, scientists from Hamburg are now investigating historical written artefacts at the X-ray radiation source PETRA III. The prominent advantage of X-ray investigations is that the artefacts can be examined without any destruction. As far as the examination method allows, no special sample preparation is required - the precious and unique objects thus remain intact.
Currently, there are two pilot studies underway. The first study deals with Mesopotamian cuneiform tablets. These millennia-old artefacts are an essential source for understanding this ancient, advanced civilization. However, many tablets that cannot be dated and originated are of limited value for research. DESY and UWA are investigating 36 objects from the Museum für Kunst und Gewerbe (MKG) and the Hamburg State and University Library (SUB) collections to understand the context of the origin of a tablet by analysing the nature of the clay. The powder diffraction method was chosen for the non-destructive and basic material characterization of this investigation. In this method, all mineral grains are detected by the X-ray beam in a local area, and these thus contribute to a characteristic diffraction pattern for a specific part of the clay tablet. The diffraction pattern consists of individual diffraction reflections for each contained mineral and gives atomic-level information about the crystalline structure. With suitable software, the mineral components can be analysed, and thus an insight into the atomic structure - as well as the quantitative composition - of these minerals can be obtained.
The second study revolves around 65 tsakalis – Tibetan written artefacts that belong to the Bon religion from the 15th to the 17th centuries. These are cards with spiritual drawings and texts that were used for meditation and initiation rites. They were made by a master, especially for his students. This study aims to find out whether the non-destructive material characterisation methods Small-Angle X-ray Scattering (SAXS) and Wide-Angle X-ray Scattering (WAXS) at the SAXSMAT beamline at DESY can provide quantitative information about the materials used, and their processing.