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See detailElemental 2D imaging of paintings with a mobile EDXRF system
Hocquet, François-Philippe ULg; Calvo Del Castillo, Helena ULg; Cervera Xicotencatl, Ariadna ULg et al

in Analytical and Bioanalytical Chemistry (2011), 399(9), 3109-3116

Imaging techniques are now used commonly and intensively in cultural heritage object analysis. Nowadays, many different techniques in nature as well as many applications exist, where they can be applied ... [more ▼]

Imaging techniques are now used commonly and intensively in cultural heritage object analysis. Nowadays, many different techniques in nature as well as many applications exist, where they can be applied. X-ray radiography and infrared reflectography as well as UV photography are some of the most applied techniques. The study of works of art usually requires these techniques to be non-invasive. Furthermore, they are frequently required to perform in situ analysis. A few years ago, our laboratory developed a mobile energy-dispersive X-ray fluorescence and UV-vis-NIR coupled spectrometer, especially designed for fieldwork studies, where all three techniques can be applied strictly at the same site of analysis. Recent developments on a new positioning system have now allowed us to perform 2D elemental mappings with our equipment, which is especially well adapted to painting analysis. The system control is carried out entirely through a laptop computer running a dedicated homemade software. The positioning is achieved by means of a CCD camera embedded in the system and controlled via a Wi-Fi connection through the computer. The data acquisition system, which is made through a homemade multichannel pulse height analyzer, being also managed via the software mentioned above, goes through an Ethernet connection. We will present here the new developments of the system and an example of in situ 2D elemental mapping applied on an anonymous oil painting on wood panel. The discovery of a hidden painting under this oil painting makes it a good choice for a first example of 2D large scan with a mobile instrument. © Springer-Verlag 2010. [less ▲]

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See detailTowards calibration and characterization of high-energy beams using charged particle retrodiffusion on a double thin carbon foil system
Chene, Grégoire ULg; Mathis, François ULg; Dupuis, Thomas ULg et al

in Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (2010), 268(11-12), 2015-2018

The cyclotron of the IPNAS-CEA laboratory of the University of Liege (Belgium) has built a new high-energy, high-resolution beam line based on the use of a pair of 900 bending magnets showing a energy ... [more ▼]

The cyclotron of the IPNAS-CEA laboratory of the University of Liege (Belgium) has built a new high-energy, high-resolution beam line based on the use of a pair of 900 bending magnets showing a energy resolution of Delta E = 1.9 +/- 0.4 keV comparable to that of electrostatic IBA installations. In the 6-20 MeV energy range the contribution of non-Rutherford events to scattering spectra became important and are not very well known. In order to improve our knowledge in that field, a new vacuum chamber especially dedicated to differential cross-section measurements has been constructed. First results obtained with the new set-up are presented. (C) 2010 Elsevier B.V. All rights reserved. [less ▲]

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See detailA remote controlled XRF system for field analysis of cultural heritage objects
Hocquet, François-Philippe ULg; Garnir, Henri-Pierre ULg; Marchal, André ULg et al

in X-Ray Spectrometry [=XRS] (2008), 37(4), 304-308

X-ray fluorescence (XRF) is a nondestructive, multielemental, fast and cost-effective analysis technique. It can be applied in a nonvacuum environment directly on the samples without any preparation. As ... [more ▼]

X-ray fluorescence (XRF) is a nondestructive, multielemental, fast and cost-effective analysis technique. It can be applied in a nonvacuum environment directly on the samples without any preparation. As archaeological and historical objects are often unique and may not be easily movable, a mobile XRF detector system allowing in situ analysis is ideally suited for archaeometric applications. A mobile system was designed and built at the IPNAS laboratory to provide such analyses. The system includes an industrial grade x-ray generator which supplies the primary x-ray beam, an air-cooled silicon rift Detector detector (SDD) with a 5-mm(2) active area. The data acquisition system measures the energy and the intensity of the secondary fluorescence x-rays. The detector signal is amplified and analyzed by a multichannel recorder coupled to a microcomputer running JavaSpectre which visualizes and analyzes spectra obtained from the detector. The detection head, containing the detector, the x-ray tube and its power supply, are fixed on a movable platform allowing independent vertical and horizontal movement. All displacements are controlled by a hand-held personal digital assistant (PDA) (Palm) which exchanges data with microcontrollers embedded in the system providing a very precise positioning of the detector over a surface of many square meters. This system control, as well as a typical application of this XRF spectrometer for analyzing pigment composition of a wall painting, will be described. Copyright (C) 2008 John Wiley & Sons, Ltd. [less ▲]

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See detailLifetime and transition probability determination in xenon ions - The cases of XeVII and XeVIII
Biémont, Emile ULg; Clar, Mathieu ULg; Fivet, V. et al

in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2007), 44(1), 23-33

Radiative lifetimes have been calculated for 15 levels of Xe VII belonging to the configurations 5s5p, 5p(2), 5s5d, 5s6s, 5p5d, 4f5p, 5p5d and 5s5f and for 4 levels of the 5p and 5d configurations of Xe ... [more ▼]

Radiative lifetimes have been calculated for 15 levels of Xe VII belonging to the configurations 5s5p, 5p(2), 5s5d, 5s6s, 5p5d, 4f5p, 5p5d and 5s5f and for 4 levels of the 5p and 5d configurations of Xe VIII. A relativistic Hartree-Fock approach including core-polarization effects, on the one hand, and a purely relativistic multiconfiguration Dirac-Fock method, on the other hand, have been used for the calculations. The accuracy of the present set of results has been assessed through comparisons with radiative lifetime measurements obtained by beam-foil spectroscopy. A good agreement between theory and experiment is observed for most of the levels. A new set of transition probabilities is proposed for 169 transitions of Xe VII and 45 transitions of Xe VIII. [less ▲]

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