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S C I E N T I F I C H I G H L I G H T S

C U LT U R A L H E R I T A G E , A R C H A E O L O G Y A N D P A L A E O N T O L O G Y

The community of ESRF users working in the field of cultural and natural heritage is small (~1% of the total ESRF users) but clearly growing. Since the restart of user operation in 2020, following the Extremely Brilliant Source (EBS) upgrade, two main actions have contributed to boost this activity.

Historical materials Block Allocation Group (BAG)

Through this new collaborative access mode, users have access to regular beamtime at two diffraction beamlines (ID22 for high-angular-resolution X-ray powder diffraction (XRPD) and ID13 for micro-XRPD mapping), for a period of three years. Over the last two years, 50 users have benefitted from this access, more than half being first-time ESRF users. As shown on page 148 with the example of the detection of lead formates in Rembrandt s painting The Night Watch, fragments from historical or model paintings are the most studied materials, but research is also carried out on various historical and cultural objects such as wood, ceramics, or papyri as illustrated on page 152 with the example of Egyptian papyrus. This new mode of access not only eases all aspect of experiments (from proposal submission to evaluation, beamtime scheduling and beamline set-up, etc.), it has also motivated the improvement of data collection and processing. In addition, these regular multi-user experiments (usually at least six people per experiment) have a clear impact on the creation and training of the future generation of heritage scientists familiar with synchrotron techniques. Beyond ID22 and ID13, this facilitated access has been, for some research groups, a first step towards complementary analyses (for example, X-ray absorption spectroscopy (XAS) at ID21, ID16B or ID24/ BM23) or 3D X-ray diffraction (XRD) at ID11. As shown on page 150 with the example of the passepartout of Leonardo da Vinci s Codex Atlanticus, this leads to multi-technique characterisations, which is particularly important considering the complexity of artistic materials.