Particle induced X-ray emission spectroscopy (PIXE) is now routinely used in the field of cultural heritage. Various setups have been developed to investigate the elemental composition of wood/canvas paintings or of cross-section samples. However, it is not possible to obtain information concerning the quantity of organic binder. Backscattering spectrometry (BS) can be a useful complementary method to overcome this limitation. In the case of paint layers, PIXE brings the elemental composition (major elements to traces) and the BS spectrum can give access to the proportion of pigment and binder. With the use of 3 MeV protons for PIXE and BS simultaneously, it was possible to perform quantitative analysis including C and O for which the non-Rutherford cross sections are intense. Furthermore, with the use of the same conditions for PIXE and BS, the experiment time and the potential damage by the ion beam were reduced. The results obtained with the external beam of the Accélérateur Grand Louvre pour l'Analyse Elementaire (AGLAE) facility on various test painting samples and on cross sections from Italian Renaissance masterpieces are shown. Simultaneous combination of PIXE and BS leads to a complete characterization of the paint layers: elemental composition and proportion of the organic binder have been determined and thus provide useful information about ancient oil painting recipes.
Scanning XRF is a powerful elemental imaging technique introduced at the synchrotron that has recently been transposed to laboratory. The growing interest in this technique stems from its ability to collect images reflecting pigment distribution within large areas on artworks by means of their elemental signature. In that sense, scanning XRF appears highly complementary to standard imaging techniques (Visible, UV, IR photography and X-ray radiography). The versatile XRF scanner presented here has been designed and built at the C2RMF in response to specific constraints: transportability, cost-effectiveness and ability to scan large areas within a single working day. The instrument is based on a standard X-ray generator with submillimetre collimated beam and a SDD-based spectrometer to collected X-ray spectra. The instrument head is scanned in front of the painting by means of motorised movements to cover an area up to 300 9 300 mm 2 with a resolution of 0.5 mm (600 9 600 pixels). The 15-kg head is mounted on a stable photo stand for rapid positioning on paintworks and maintains a free side-access for safety; it can also be attached to a lighter tripod for field measurements. Alignment is achieved with a laser pointer and a micro-camera. With a scanning speed of 5 mm/s and 0.1 s/point, elemental maps are collected in 10 h, i.e. a working day. The X-ray spectra of all pixels are rapidly processed using an open source program to derive elemental maps. To illustrate the capabilities of this instrument, this contribution presents the results obtained on the Belle Ferronnière painted by Leonardo da Vinci (1452-1519) and conserved in the Musée du Louvre, prior to its restoration at the C2RMF.
▶ Covers the full spectrum of natural scientific methods with an emphasis on the archaeological contexts and the questions being studied ▶ Bridges the gap between archaeologists and natural scientists Archaeological and Anthropological Sciences covers the full spectrum of natural scientific methods with an emphasis on the archaeological contexts and the questions being studied. It bridges the gap between archaeologists and natural scientists providing a forum to encourage the continued integration of scientific methodologies in archaeological research.Coverage in the journal includes: archaeology, geology/geophysical prospection, geoarchaeology, geochronology, palaeoanthropology, archaeozoology and archaeobotany, genetics and other biomolecules, material analysis and conservation science.
The
sophisticated colors of medieval glasses arise from their transition
metal (TM) impurities and capture information about ancient glassmaking
techniques. Beyond the glass chemical composition, the TM redox is
also a key factor in the glass color, but its quantification without
any sampling is a challenge. We report a combination of nondestructive
and noninvasive quantitative analyses of the chemical composition
by particle-induced X-ray emission–particle-induced γ-ray
emission mappings and of the color and TM element speciation by optical
absorption spectroscopy performed on a red-blue-purple striped glass
from the stained glass windows of the Sainte-Chapelle in Paris, France,
during its restoration. These particular glass pieces must have been
produced as a single shot, which guarantees that the chemical variations
reflect the recipe in use in a specific medieval workshop. The quantitative
elemental mappings demonstrate that the colored glass parts are derived
from the same base glass, to which TMs were deliberately added. Optical
absorption spectra reveal the origin of the colors: blue from CoII, red from copper nanoparticles, and purple from MnIII. Furthermore, the derivation of the quantitative redox state of
each TM in each color shows that the contents of Fe, Cu, and Mn were
adjusted to ensure a reducing glass matrix in the red stripe or a
metastable overoxidized glass in the purple stripe. We infer that
the agility of the medieval glassmaker allowed him to master the redox
kinetics in the glass by rapid shaping and cooling to obtain a snapshot
of the thermodynamically unstable glass colors.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.