 PUMA, a beamline optimized for ancient matierials
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In terms of synchrotron equipment, the priority established by the objectives defined by the communities concerned has been for both 2D and 3D X-ray imaging. These imaging methods are indeed the most frequently requested for understanding the morphology, composition, structure and properties of ancient materials.
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The proposed PUMA beamline (Photons Used for Ancient Materials) will aim to supply two experimental stations: one for hard X-ray spectro-microscopy (2D imaging and electron probe microanalysis), the other for hard X-ray micro-tomography (3D imaging). Both branches will aim for a resolution of the order of one micrometer.
The line will be optimized to minimize setup time and facilitate the measurement of large collections of samples.
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As for IPANEMA as a whole, the creation of PUMA has been based on a large collective effort that culminated in May 2009 with the conference "A Beamline for ancient materials at SOLEIL."
On this basis, the optics group is creating an optical plan for the beamline, taking into account the numerous recommendations of the scientific community.
Key steps in creating the PUMA beamline include:
- June 2009: presentation of the outline plan to the Scientific Council at SOLEIL
- 2011: construction and constitution of the preliminary design summary,
- 2012: detailed draft and specifications for PUMA.
The opening of the beamline is planned for 2015/2016.
Optical plan of the beamline : 
Model of the beamline : 
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X-ray absorption and diffraction
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X-ray absorption is used to determine the electronic and atomic environments of a given element, through the use of two main methods: X-ray absorption near edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS). In archaeometry, art history or conservation, these methods are used mainly to determine the precise environment of the atoms in question, often to confirm their oxidation state or using reference data to identify a chemical compound. Accurate distances from their nearest neighbors can be determined [1].
Main corresponding beamlines at SOLEIL :
• SAMBA and ODE for hard X-ray absorption spectroscopy
• DIFFABS and LUCIA in micro-imaging mode
• In the future, PUMA and NANOSCOPIUM
X-ray diffraction is used to identify the crystalline components of a sample (powder, thin section, bulk samples) or to determine the atomic-scale structure of a crystalline compound. Detailed analysis provides access to crystallite size, texture (preferred orientation), structural defects, etc. and can therefore reveal mechanical or heat treatment (heating, hammering ...) Examples in the heritage field include in-situ monitoring of the preparation of pigments [2] and the analysis of ancient cosmetic powders [3], etc.
Main corresponding beamlines at SOLEIL :
• CRISTAL, for hard X-ray diffraction
• DIFFABS and NANOSCOPIUM in micro- and nano-imaging modes, respectively
• In the future, PUMA
Small-angle X-ray scattering (SAXS) is used mainly to determine the 'supramolecular' organization of ancient fibers (protein, cellulose ...) in textiles, parchment, paper and human remains, or to determine the pore distribution in a sample. This method is also used to identify fibers in a degraded state, to assess the state of conservation of textiles [4] or to clarify diagenetic processes [5].
Main corresponding beamlines at SOLEIL :
• SWING, for hard X-ray scattering
Selected references :
[1] S. Padovani et al. XAFS study of copper and silver nanoparticles in glazes of medieval Middle-East lustreware (10th-13th century). Appl. Phys. A, 83:521-528, 2006. [ .html ]
[2] T. Pradell, N. Salvado, G. D. Hatton, et M. S. Tite. Physical processes involved in production of the ancient pigment, Egyptian blue. J. Am. Ceram. Soc., 89(4):1426-1431, April 2006. [ .html ]
[3] P. Walter, P. Martinetto, G. Tsoucaris, R. Bréniaux, M. A. Lefebvre, G. Richard, J. Talabot, et É. Dooryhée. Making make-up in ancient Egypt. Nature, 397:483-484, 1999. [ .html ]
[4] C. J. Kennedy, M. Vest, M. Cooper, et T. J. Wess. Laser cleaning of parchment: structural, thermal and biochemical studies into the effect of wavelength and fluence. Appl. Surf. Sci., 227(1-4):151-163, 2004. [ .html ]
[5] L. Bertrand, J. Doucet, P. Dumas, A. Simionovici, G. Tsoucaris, et P. Walter. Microbeam synchrotron imaging of hairs from Ancient Egyptian mummies. J. Synchrotron Radiat., 10(5):387-392, September 2003. [ .html ]
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X-ray micro-tomography
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Some characteristics of synchrotron radiation (monochromatic, very high intensity, quasi-parallel beam and coherence) are particularly suited to the study of samples difficult to image using conventional radiography and tomography equipment. In particular, the 'beam hardening' effect seen with laboratory polychromatic X-ray sources is eliminated and the contrast in material that is relatively homogeneous in density can be increased significantly in the 'phase contrast' mode. Much recent work on synchrotron tomography beamlines has been carried out on paleontological samples [1].
Corresponding beamlines on SOLEIL :
• PUMA, for phase-contrast X-ray micro-tomography (opening in 2012/2013)
• PSICHE, for X-ray absorption micro-tomography (opening 2011)
Selected references :
[1] P. Tafforeau et al. Applications of X-ray synchrotron micro-tomography for non-destructive 3D studies of paleontological specimens. Appl. Phys. A, 83(2):195-202, May 2006. [ .html ]
[2] X. P. Dong et al. The anatomy, taphonomy, taxonomy and systematic affinity of markuelia: early cambrian to early ordovician scalidophorans. Palaeontol., 53:1291–1314, Nov 2010.
[3] A. Pradel et al. Skull and brain of a 300-million-year-old chimaeroid fish revealed by synchrotron holotomography. Proc. Natl Acad. Sci. USA, 106(13):5224–5228, Mar 2009.
[4] C. Soriano et al. Synchrotron x-ray imaging of inclusions in amber. C. R. Palevol, 9(6-7):361–368, 2010.
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2D micro-imaging
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Infrared and X-ray microbeams (i.e. beams with a diameter of a micrometer or less) are used either for electron probe analysis on micro-samples or to acquire 2D (or 3D) raster scans. Such scans provide access to composition (XRF), local chemistry (X-ray absorption, infrared microscopy) and structure (XRD) at a micrometer scale, thereby providing crucial information for understanding materials and to study aging and the treatments that are being (or have been) applied [1-3].
Using multi-technique synchrotron beamlines, different kinds of information can be collected at the same acquisition point. By reducing the beam size, it is possible to reduce the complexity of the analysis of a heterogeneous material, the number of species contributing to each spectrum itself tending to decrease.
Corresponding beamlines on SOLEIL :
• SMIS, for infrared micro-spectroscopy
• LUCIA, for soft X-ray micro-spectroscopy
• DIFFABS, for hard X-ray micro-diffraction and micro-absorption
• DISCO, pour UV-visible luminescence micro-imaging
• In the future, PUMA and NANOSCOPIUM, for hard X-ray micro and nano-imaging, respectively.
Selected references:
[1] S. Reguer, P. Dillmann, F. Mirambet, J. Susini, et P. Lagarde. Investigation of Cl corrosion products of iron archaeological artefacts using micro-focused synchrotron X-ray absorption spectroscopy. Appl. Phys. A, 83(2):189-193, May 2006. [ .html ]
[2] M. Sandström, F. Jalilehvand, I. Persson, U. Gelius, P. Frank, et I. Hall-Roth. Deterioration of the seventeenth-century warship Vasa by internal formation of sulphuric acid. Nature, 415(6874):893-897, February 2002. [ .html ]
[3] L. Bertrand. Synchrotron imaging for archaeology, art history, conservation and paleontology, in Physical Principles in Art and Archaeometry (D. C. Creagh, ed.), in press.
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