Non-Destructive High-Resolution X-ray Diffraction for Cultural Heritage

Lead Research Organisation: University of Leicester
Department Name: Space Research Centre

Abstract

Many different analytical techniques are commonly applied in the scientific analysis of heritage objects in order to elucidate their material properties. Each technique has advantages and disadvantages in terms of the type of information returned, complexity and expense, sample preparation requirements and applicability to different types of material objects. While X-ray fluorescence (XRF) is very useful in providing elemental information, and techniques such as Fourier-transform infrared spectroscopy and Raman spectroscopy can yield phase information, only X-ray diffraction (XRD) allows the definitive and unambiguous identification of crystallographic phases. Despite this, the use of XRD in archaeometry has been relatively sporadic and of utility only in niche areas, largely because of sample preparation requirements. This project aims to bring exciting advances in non-destructive XRD techniques to the archaeometric analysis of cultural heritage and archaeological artefacts. The innovative XRD methods developed by the applicants enable high resolution XRD analysis of objects with no sample preparation requirement at all. While twenty years ago sampling of artefacts was considered standard practice, the growth of non-destructive techniques such as handheld XRF have made curators at museums and other collections very much less willing to allow invasive procedures. Maintaining the physical integrity of heritage artefacts is now considered to be of paramount importance.

There are certain classes of heritage objects for which destructive sampling is currently the only realistic approach to determining provenance. Stone artefacts are a primary example. Many stone objects in Western Museums are from the art market and doubts have been expressed about the authenticity of many. The most effective method of provenancing stone artefacts is the detailed characterisation of the mineralogical composition in order to identify the geological source, but destructive sampling is nearly always currently required for this purpose. A second major application area is the identification of pigments in fine art paintings and on painted objects such as mummy portraits and Indian miniatures. Although Raman spectroscopy can successfully identify a significant proportion of pigments, there remain an important number for which the method is ineffective. Pigments have unique diffraction pattern fingerprints and XRD studies can provide the critical information for essentially all pigments. The study of stone artefacts and of paintings and painted artefacts will form a major focus of the proposed project.

Currently, this innovative XRD technique requires synchrotron facilities for implementation. The applicants will demonstrate the method using cutting-edge high-resolution X-ray detectors (superconducting transition-edge sensor arrays) at the National Institute of Standards and Technology in the US in proof-of-principle experiments. This work will support the eventual transition of the technique away from synchrotrons and into the laboratory and museum. An additional aim is to investigate the archaeometric capability of a prototype handheld XRD instrument, based on the same underlying technique but having much lower resolution. Previous work with this prototype device strongly suggests that the analysis of metallic heritage objects is an especially promising area.

The avoidance of the need to extract samples from high-value and rare objects is a highly-significant advantage and is applicable in other research areas. These include palaeontology and the study of meteorites and planetary materials brought to Earth by sample-return missions.

Planned Impact

The uniqueness of this research lies in the ability to perform highly accurate crystallographic analysis without the need for any preparation of the sample, even for markedly non-planar and textured objects. This capability is greatly enabling, opening up new opportunities for detailed investigations of the crystallographic material properties of a wide range of objects.

Museums and their curators will benefit from access to the new knowledge generated during the project and, in the longer term, through the establishment of highly capable XRD analytical facilities situated within larger museums with more extensive collections. The new knowledge will lead to improved explanatory and contextual information displays about collections. Access to up-to-date research will support museums as evolving entities within communities, contributing to individual and societal well-being and supporting economic tourism and so benefiting the wider public.

There is potential for further significant economic impact through verification of the authenticity of artworks, directly benefiting auction houses and insurance companies. For example, the identification of pigments can place strong constraints on the date and location of manufacture and this information is extremely valuable for high-worth artworks. Buyers of art, including museums, will benefit through assurance of the veracity of their purchases. The UK is home to several internationally-leading auction houses (Christies, Sothebys, Bonhams) and the proposed research will support these leading roles, ultimately to the benefit of the UK economy.

The PDRA employed on the project will receive first-class cross-disciplinary scientific training at the Universities of Leicester and Cranfield. S/he will develop key employability skills, including communication, presentation and organisational skills and team working. Summer students will also be employed on the project and will have the opportunity to gain an invaluable insight into cutting-edge research, guiding their decisions about future careers.

Publications

10 25 50
 
Description The overarching purpose of this research project was the application of a unique X-ray diffraction (XRD) methodology which is almost completely impervious to the morphology of the sample, in contrast to conventional XRD methods. When implemented at high resolution at the Diamond Light Source synchrotron, the technique returns very high quality diffraction data, entirely non-invasively; this combination of characteristics represents the holy grail within cultural heritage materials research. A series of visits to Diamond were made in order to validate the technique for a wide range of heritage artefact types, including paintings, high-value Chinese porcelain, wall painting fragments, and stone and rock objects such as Roman white marble. The technique was shown to be effective in the material analysis of heritage objects and detailed knowhow was developed in how to optimise the measurements.
Exploitation Route The PI is currently writing a proposal to the EPSRC strategic equipment fund for a TES spectrometer in order to transition the technique away from the synchrotron and into the laboratory and museum. The capability to take the instrument to the objects to make in situ measurements will enable transformative research in the field of cultural heritage. The PI plans to establish an advanced facility that can be accessed by a range of users, including industrial partners in aerospace, for example.
Sectors Aerospace, Defence and Marine,Manufacturing, including Industrial Biotechology,Culture, Heritage, Museums and Collections

 
Description Knowledge Exchange, Impact & Proof of Concept Development Fund Application
Amount £13,127 (GBP)
Organisation University of Leicester 
Sector Academic/University
Country United Kingdom
Start 04/2022 
End 07/2022
 
Description Proof of Concept Fund 2019-20 Call 8
Amount £5,000 (GBP)
Organisation University of Leicester 
Sector Academic/University
Country United Kingdom
Start 02/2020 
End 06/2020
 
Description Research Equipment and Infrastructure Fund - Stand Alone call 2018/19
Amount £39,428 (GBP)
Organisation University of Leicester 
Sector Academic/University
Country United Kingdom
Start 03/2019 
End 07/2019
 
Title Crystalline Phase Quantification with Energy-Dispersive XRD Data using Rietveld Analysis 
Description The quantification of crystalline phases in a mixture is relatively unusual in energy-dispersive XRD because of the difficulty in accounting for the variation in the relevant parameters with X-ray energy, amongst other reasons. We have developed methods which can overcome this problem either by segmenting the data into relatively short ranges over which variation of parameters is small, or by applying an overall scaling function (with a small number of fitted parameters) to account for the variations. 
Type Of Material Data analysis technique 
Year Produced 2019 
Provided To Others? No  
Impact This method is having significant impact within our own research, enabling the relative quantification of the crystalline phases in artistic paints, for example. We plan to publish this method in 2020. 
 
Description Analysis of wall paintings/fragments with the Courtauld 
Organisation Courtauld Institute of Art (University of London)
Country United Kingdom 
Sector Academic/University 
PI Contribution Application of a non-invasive but high resolution XRD technique at the Diamond synchrotron, including data acquisition and processing, and crystallographic interpretation.
Collaborator Contribution Provision of wall painting fragments from the Courtauld archive and expert interpretation of the analytical results from an art historical perspective.
Impact No outcomes as yet. Highly multidisciplinary: X-ray physics, materials analysis by XRD and XRF (crystallographic and elemental analyses), and art historical interpretation.
Start Year 2018
 
Description Collaboration with NIST in order to test the efficacy of TES array detectors for high-resolution back-reflection EDXRD 
Organisation National Institute of Standards & Technology (NIST)
Department Quantum Sensors Group
Country United States 
Sector Public 
PI Contribution The collaboration centres on a short experimental campaign on the application of NIST superconducting transition-edge sensor arrays in non-destructive XRD analysis of cultural heritage objects. The campaign is currently at a planning stage and was expected to take place in late 2020. The pandemic has delayed these plans because it involved travel of staff from the UK to the USA. As of Feb 2022, NIST has put together a vacuum chamber for testing and a set of samples have been sent to NIST. The experiments are expected to be completed by the end of April 2022.
Collaborator Contribution Information concerning the performance, operation and cost of superconducting TES arrays. Support of planning the experimental campaign.
Impact No outcomes as yet. Disciplines involved: superconducting sensors and readout electronics, x-ray diffraction, x-ray physics
Start Year 2016
 
Description Corrosion analysis of Mary Rose cannonballs using handheld XRD and synchrotron XRD 
Organisation Mary Rose Trust
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution We are investigating the capabilities of a prototype handheld XRD instrument in the analysis of the corrosion of iron-based cultural heritage artefacts, specifically applied to cannonballs from the Mary Rose. The contribution has been the provision of the prototype instrument, data acquisition and processing. In addition, we are sourcing pure mineral samples to make up representative mixtures for comparative measurements. We have also conducted non-destructive synchrotron XRD measurements on the same samples (analysis yet to be done).
Collaborator Contribution Provision of samples in the form of Mary Rose cannonballs (or fragments).Interpretation of the results from a cultural heritage perspective, especially relating to the conservation of iron artefacts.
Impact No outcomes as yet. Highly multidisciplinary - X-ray physics, materials analysis by XRD and XRF (mineralogical and elemental analyses), cultural heritage and conservation.
Start Year 2017
 
Description Corrosion analysis of Mary Rose cannonballs using handheld XRD and synchrotron XRD 
Organisation University College London
Department Institute of Archaeology
Country United Kingdom 
Sector Academic/University 
PI Contribution We are investigating the capabilities of a prototype handheld XRD instrument in the analysis of the corrosion of iron-based cultural heritage artefacts, specifically applied to cannonballs from the Mary Rose. The contribution has been the provision of the prototype instrument, data acquisition and processing. In addition, we are sourcing pure mineral samples to make up representative mixtures for comparative measurements. We have also conducted non-destructive synchrotron XRD measurements on the same samples (analysis yet to be done).
Collaborator Contribution Provision of samples in the form of Mary Rose cannonballs (or fragments).Interpretation of the results from a cultural heritage perspective, especially relating to the conservation of iron artefacts.
Impact No outcomes as yet. Highly multidisciplinary - X-ray physics, materials analysis by XRD and XRF (mineralogical and elemental analyses), cultural heritage and conservation.
Start Year 2017
 
Description Cultural Heritage with Dr Andrew Shortland 
Organisation British Museum
Country United Kingdom 
Sector Public 
PI Contribution Non-destructive X-ray diffraction (XRD) analysis of archaeological objects using a novel XRD technique which is insensitive to the sample morphology. X-ray fluorescence (XRF) analysis of the same objects. Interpretation of the XRD/XRF data in terms of composition.
Collaborator Contribution Provision of samples for XRD analysis and expert interpretation of the archaeological significance of the compositional analysis.
Impact No outcomes as yet. A paper has been published in the prestigious Advances section of Acta Crystallographica A journal. Highly multidisciplinary - X-ray physics, materials analysis by XRD and XRF (mineralogical and elemental analyses), archaeological.
Start Year 2014
 
Description Cultural Heritage with Dr Andrew Shortland 
Organisation Cranfield University
Country United Kingdom 
Sector Academic/University 
PI Contribution Non-destructive X-ray diffraction (XRD) analysis of archaeological objects using a novel XRD technique which is insensitive to the sample morphology. X-ray fluorescence (XRF) analysis of the same objects. Interpretation of the XRD/XRF data in terms of composition.
Collaborator Contribution Provision of samples for XRD analysis and expert interpretation of the archaeological significance of the compositional analysis.
Impact No outcomes as yet. A paper has been published in the prestigious Advances section of Acta Crystallographica A journal. Highly multidisciplinary - X-ray physics, materials analysis by XRD and XRF (mineralogical and elemental analyses), archaeological.
Start Year 2014
 
Description Cultural Heritage with Prof Patrick Degryse 
Organisation University of Leuven
Country Belgium 
Sector Academic/University 
PI Contribution Non-destructive X-ray diffraction (XRD) analysis of archaeological objects using a novel XRD technique which is insensitive to the sample morphology. X-ray fluorescence (XRF) analysis of the same objects. Interpretation of the XRD/XRF data in terms of composition.
Collaborator Contribution Provision of samples for XRD analysis and expert interpretation of the archaeological significance of the compositional analysis. Provisions of advice and feedback for a grant application to the EPSRC.
Impact No outcomes as yet. A paper has been published in the prestigious Advances section of Acta Crystallographica A journal. Highly multidisciplinary - X-ray physics, materials analysis by XRD and XRF (mineralogical and elemental analyses), archaeological.
Start Year 2014
 
Description Conference Talk - A High-Resolution Non-Invasive XRD Technique for Cultural Heritage 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Presentation at the Synchrotron Radiation and Neutrons in Art and Archaeology 2018 conference of a novel X-ray diffraction method which is completely non-destructive and therefore highly applicable to archaeological and artwork research. The purpose of the presentation was to advertise this research to the cultural heritage community. One possible collaboration is a direct result of this presentation.
Year(s) Of Engagement Activity 2018