Type: Spectroscopic point analysis
This is a transportable XRD-XRF device that can be operated for field work. It is an integrated system which permits simultaneous X-ray fluorescence and X-ray diffraction analyses to be carried out in the same position. The acquisition of the XRD patterns is done in reflection mode to avoid any contact with the works of art. The prototype instrument allows the characterization of the main materials characteristics: determination of the different phases (chemical composition, crystal structure) and the description of the microstructure (grain size, texture, lattice imperfections, etc.). Validation measurements have been carried out on different types of objects, such as paintings, ceramics and metals. The XRD diagrams obtained with the portable XRF/XRD instrument are comparable in quality with diagrams obtained with conventional laboratory equipment.
The X-rays source is a copper anode tube, with a maximum 40Wpower:40 kV,1 mA. A collimating polycapillary system gives a quasi parallel outgoing beam with a very low divergence. The diameter of the beam is about 4 mm. The XRF signal is collected with a SDD X fluorescence detector with a resolution less than 140 eV at 5.9 keV. The recording of the XRD patterns is performed with asilicon pixel detector (XPAD S70)of a 75 x 15 mm area with 67200 pixels; with a quantum efficiency of 99 % for 9 keV and 70 % for 15 keV. The system satisfies the requirements of the NF standard on the use of X rays.
Data treatment is aided by a database used in cultural heritage (mineral and organic phases), and permits at least a semi quantitative identification of the crystalline phase.
- A. Gianoncelli, J. Castaing, L. Ortega, E. Doorhycée, J. Salomon, P. Walter, J.-L. Hodeau, P. Bordet, “A portable instrument for in situ determination of the chemical and phase compositions of cultural heritage objects”, X ray spectrometry, vol.37, (2008) 418-423M.
- Eveno, A. Duran, et J. Castaing, “A portable X-ray diffraction apparatus for in situ analyses of masters’ paintings “, Applied Physics A, vol. 100, no 3,(2010), 577‑584.
- L. Beck, H. Rousselière, J. Castaing, A. Duran, M. Lebon, B. Moignard, et F. Plassard, “First use of portable system coupling X-ray diffraction and X-ray fluorescence for in-situ analysis of prehistoric rock art “, Talanta, vol. 129, (2014), 459‑464.
MOLAB France: CNRS-C2RMF