References of "Mathis, François"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailPIXE identification of the provenance of ferruginous rocks used by Neanderthals
Mathis, François ULg; Bodu, Pierre; Dubreuil, Olivier ULg et al

in Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (in press)

Les Bossats, near Ormesson, France, is a newly discovered late Mousterian open air site dated to around 47,000 years ago by thermoluminescence. The archaeological level, fossilized by loess, revealed a ... [more ▼]

Les Bossats, near Ormesson, France, is a newly discovered late Mousterian open air site dated to around 47,000 years ago by thermoluminescence. The archaeological level, fossilized by loess, revealed a rich industry based on the discoid mode, associated with numerous fragments of red and yellow iron oxide-rich rocks showing clear traces of powder production (abrasion, striation, scraping), which are exceptional remains for this remote period. Archeological material and geological samples from the close environment were studied by PIXE and by petrographical observations made on thin sections. The geological sources were identified by means of PIXE analyses on two IBA facilities: AGLAE (2 MV tandem) at the C2RMF in Paris and the cyclotron of the IPNAS (University of Liège). We paid particular attention to the comparison of results obtained on both installations by using the same set of geological standards and by a fine evaluation of the limit of detection relative to each trace elements of interest for both experimental set ups. The elemental fingerprint of one geological source of iron-rich concretions corresponds clearly with the archaeological collection. At least, this investigation demonstrates that the colouring materials were minutely selected in the close neighbouring of the site by the Neanderthals. [less ▲]

Detailed reference viewed: 23 (7 ULg)
Full Text
Peer Reviewed
See detailPore-filling of Spiro-OMeTAD determined by Rutherford backscattering spectrometry in templated TiO2 photoelectrodes
Dewalque, Jennifer ULg; Colson, Pierre ULg; Thalluri, Venkata Visveswara Gopala Kris ULg et al

in Organic Electronics (2014), 15

Liquid-state dye-sensitized solar cells can suffer from electrolyte evaporation and leakage. Therefore solid-state hole transporting materials are investigated as alternative electrolyte materials ... [more ▼]

Liquid-state dye-sensitized solar cells can suffer from electrolyte evaporation and leakage. Therefore solid-state hole transporting materials are investigated as alternative electrolyte materials. However, in solid-state dye-sensitized solar cells, optimal TiO2 films thickness is limited to a few microns allowing the adsorption of only a low quantity of photoactive dye and thus leading to poor light harvesting and low conversion efficiency. In order to overcome this limitation, high surface area templated films are investigated as alternative to nanocrystalline films prepared by doctor-blade or screen-printing. Moreover, templating is expected to improve the pore accessibility what would promote the solid electrolyte penetration inside the porous network, making possible efficient charge transfers. In this study, films prepared from different structuring agents are discussed in terms of microstructural properties (porosity, crystallinity) as well as impact on the dye loading and Spiro-OMeTAD (2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)9,9'-spirobifluorene) solid electrolyte filling. We first report Rutherford backscattering spectrometry as an innovative non-destructive tool to characterize the hole transporting materials infiltration. Templated films show dye loading more than two times higher than nanocrystalline films prepared by doctor-blade or screen-printing and solid electrolyte infiltration up to 88%. [less ▲]

Detailed reference viewed: 89 (17 ULg)
Peer Reviewed
See detailMeasurements of non-Rutherford cross sections for 4-15 MeV alpha particles on light elements from C to Si
Chene, Grégoire ULg; Mathis, François ULg; Fleury-Frenette, Karl ULg et al

Conference (2013, September)

These last years Ion Beam Analysis users show an interest in High Energy Alpha beams[1]. These beams can be used for on-site analysis by means of radioactive sources e.g. for space application but they ... [more ▼]

These last years Ion Beam Analysis users show an interest in High Energy Alpha beams[1]. These beams can be used for on-site analysis by means of radioactive sources e.g. for space application but they also offer a powerful combination of properties for the analysis of thick layers (about 10 to 20 µm). This kind of layers is often met in cultural heritage applications but can be also present on new materials. Contrary to this kind of materials where the principal information needed is the in-depth profiles as the sample are of known composition, for cultural heritage materials the combination of elemental analysis and their in-depth distribution is essential as the nature of the material is a-priori not known. In this perspective high energy alpha beams can produce really interesting results as their PIXE cross-sections increase from 6 MeV while the lower penetration of the beam (comparing to classical protons beams) allows to limit the analysis to the layer of interest. For the elemental in depth distribution we take advantage of the good mass separation of the alpha particles and the non-Rutherford phenomena allow the analysis even of light elements which are of great interest in cultural heritage problematic as far as the cross section are well tabulated. Using two IBA facilities (AGLAE in Paris and the HE-HR beam line of the cyclotron in Liège University[2]) we explored the backscattering cross section of numerous light elements (from C to Si) from 4 to 15 MeV in order to check the lack in the literature, to verify the deviation from Rutherford law and compare it to the existing theoretical models. We begin to measure the needed cross sections using thick target in case of smooth cross section and thin layers for exploring important variation of the cross section. [less ▲]

Detailed reference viewed: 25 (1 ULg)
Peer Reviewed
See detailNanoparticles used to darken the patina of antic black bronze: TEM observations on new experimentations
Mathis, François ULg; Tirat, Sophie; Grieten, Eva et al

Conference (2013, September)

Some studies that started in the nineties [1] proved that some antic artefacts or parts were intentionally patinated using a chemical treatment. In particular one type of patina was characterized on ... [more ▼]

Some studies that started in the nineties [1] proved that some antic artefacts or parts were intentionally patinated using a chemical treatment. In particular one type of patina was characterized on artefacts coming either from Egyptian civilization, Mycenaean period or Roman Empire. This patina has been identified as a precious material mentioned in ancient Egyptian and Roman texts. This particular material is named, depending on the artefacts’ origin, black bronze (hmty km), or corinthium aes. This patina is made on copper alloys containing gold and/or silver and is composed mainly of cuprite. It was compared with a Japanese patina which appears in medieval times but which is still in use and known under the name of shakudo. Shakudo are copper gold alloys and they are treated chemically by means of different recipes named nikomi-chakushoku which developed a black layer of cuprite on the surface. An important study of antic artefacts coming from the collections of French museums has been carried out since the beginning of the 2000’s. An experimental protocol based on non-invasive analysis was developed to analyse these very precious objects and to identify and characterize this type of patina in function of the provenance and age of the artefacts [2, 3]. However, some questions about this particular surface layers could not be resolved using this experimental protocol due to the limitation of non-invasive analytical techniques: In particular the question of the formation of the oxide layer, the colouring mechanism of this black cuprite (copper oxide which is red under natural form) and the important adherence properties. We developed a program of experimentation to make some black patina. These experimentations were based on the utilisation of the Japanese recipes, and we tried to differentiate the effect of the alloying element (Au, Ag, As) and the effects of the chemical treatment. These patinas were studied by means of various analytical methods and in particular we used TEM to characterize the fine structure of the oxide layer. The use of transmission electron microscopy (TEM) allows to evidence a hypothesis already mentioned in previous studies [4]: the presence of nanoparticles of gold in the cuprite layers and their role on the coloration of the patina making the black bronze the very first applications of nanoparticles in technical history. [less ▲]

Detailed reference viewed: 27 (1 ULg)
Full Text
See detailTiO2 templated films used as photoelectrode for solid-state DSSC applications: study of the pore filling by Rutherford Backscattering Spectroscopy
Dewalque, Jennifer ULg; Colson, Pierre ULg; Thalluri, Venkata Visveswara Gopala Kris ULg et al

Poster (2013, September)

Liquid-state dye-sensitized solar cells can suffer from electrolyte evaporation and leakage. Therefore solid-state hole transporting materials are investigated as alternative electrolyte materials ... [more ▼]

Liquid-state dye-sensitized solar cells can suffer from electrolyte evaporation and leakage. Therefore solid-state hole transporting materials are investigated as alternative electrolyte materials. However, in solid-state dye-sensitized solar cells, optimal TiO2 films thickness is limited to a few microns allowing the adsorption of only a low quantity of photoactive dye and thus leading to poor light harvesting and low conversion efficiency. In order to overcome this limitation, high surface area templated films are investigated as alternative to nanocrystalline films prepared by doctor-blade or screen-printing. Moreover, templating is expected to improve the pore accessibility what would promote the solid electrolyte penetration inside the porous network, making possible efficient charge transfers. In this study, films prepared from different structuring agents are discussed in terms of microstructural properties (porosity, crystallinity) as well as effect on the dye loading and Spiro-OMeTAD (2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)9,9'-spirobifluorene) solid electrolyte filling. Different techniques such as transmission electron microscopy (TEM), atmospheric poroellipsometry (AEP) and UV-visible absorption spectroscopy (UV-vis.) have been used to describe the microstructural features of the films. Besides, we have implemented Rutherford backscattering spectrometry (RBS) as an innovative non-destructive tool to characterize the hole transporting materials infiltration. Templated films show dye loading more than two times higher than nanocrystalline films prepared by doctor-blade or screen-printing and solid electrolyte infiltration up to 88%. [less ▲]

Detailed reference viewed: 88 (18 ULg)
See detailArchaeometry Research on the Wall Paintings in the Tomb Chapel of Menna
Garcia Moreno Rodriguez, Renata ULg; Hocquet, François-Philippe ULg; Mathis, François ULg et al

in Hartwig, Melinda (Ed.) The Tomb Chapel of Menna (TT 69): The Art, Culture, and Science of Painting in an Egyptian Tomb (2013)

Detailed reference viewed: 74 (15 ULg)
Full Text
See detailTiO2 templated films used as photoelectrode for solid-state DSSC applications: study of the pore filling by Rutherford Backscattering Spectroscopy
Dewalque, Jennifer ULg; Colson, Pierre ULg; Thalluri, Venkata Visveswara Gopala Kris ULg et al

Poster (2013, July)

Mesoporous anatase thin films are very promising materials to act as electrode in dye-sensitized solar cells. Randomly oriented nanocrystalline TiO2 particles are usually used to prepare photoelectrodes ... [more ▼]

Mesoporous anatase thin films are very promising materials to act as electrode in dye-sensitized solar cells. Randomly oriented nanocrystalline TiO2 particles are usually used to prepare photoelectrodes with a thickness of 10-15 µm. However, in solid-state DSSCs, TiO2 films thickness is limited to few µm allowing the adsorption of only a low quantity of photoactive dye and thus leading to a poor light harvesting and low conversion efficiencies. In order to overcome this limitation, templated-assisted dip-coating techniques are used to obtain thin films with high surface area. Moreover, templating is expected to improve the pore accessibility what would promote the solid electrolyte penetration inside the porous network, making possible efficient charge transfers. In this study, films prepared from different structuring agents are discussed in terms of microstructure properties (porosity, crystallinity) and impact on the dye loading and solid electrolyte filling. As-obtained templated films have been compared to nanocrystalline films prepared by doctor blade or screen printing as reference. Different techniques such as transmission electron microscopy (TEM), atmospheric poroellipsometry (AEP) and UV-visible absorption spectroscopy (UV-vis.) have been used to describe the microstructural features of the films. Solid electrolyte infiltration has been extensively investigated by Rutherford Backscattering Spectroscopy (RBS). Finally, templated films were evaluated as photoelectrode in solid-state DSSCs and compared to nanoparticles layers. [less ▲]

Detailed reference viewed: 22 (7 ULg)
Peer Reviewed
See detailLes perles en verre de la nécropole de Bossut–Gottechain : recettes et fabrication
Mathis, François ULg; Vrielynck, Olivier; Leroy, Amandine et al

Conference (2013, April)

La nécropole de Bossut Gottechain est une des plus grandes nécropoles mérovingiennes jamais trouvée en Belgique. Les fouilles conduites entre 2002 et 2006 ont permis de mettre au jour 436 tombes sur une ... [more ▼]

La nécropole de Bossut Gottechain est une des plus grandes nécropoles mérovingiennes jamais trouvée en Belgique. Les fouilles conduites entre 2002 et 2006 ont permis de mettre au jour 436 tombes sur une période d’occupation s’étalant de 470 à 670 ap J.C. Ces tombes contenaient un matériel funéraire important composé d’armes, d’accessoires de vêtement, de récipients en céramique, en métal et en verres, et de bijoux parmi lesquels une quantité inhabituellement importante de perles. Plus de 8000 spécimens ont été retrouvés, la majorité en verre (environ 6800 soit 82% du corpus), mais aussi en ambre, pierre, céramique ou métal. L’abondance de ce matériel et la datation fine de ce site ont permis de dresser une typo-chronologie précise de cette production affinant la description des types et des périodes d’utilisation déjà connus. Nous avons voulu en plus de l’étude purement archéologique de ces perles porter une attention particulière au matériau qui les compose. Une campagne d’analyse physico-chimique a donc été engagée. La méthode choisie a été la spectroscopie PIXE- PIGE en faisceau extrait, cette méthode d’analyse non invasive et très sensible aux éléments légers étant particulièrement adaptée à notre corpus d’objets nombreux mais précieux. Ces analyses ont été conduites sur la ligne de faisceau extrait ARCHEO de l’accélérateur de l’Institut de Physique Nucléaire, Atomique et de Spectroscopie de l’université de Liège. Nous avons pu analyser plus de trois cent perles. Une attention particulière a été portée sur les perles en verres jaune et noire, abondamment représentées dans le corpus, ainsi que sur plusieurs perles dont le type rare ou unique sur le site nous interrogeait. Les résultats de cette recherches ont été particulièrement fructueux car nous avons pu mettre en exergue la pratique connue du remploi de perles en verre romain ou protohistorique à l’époque mérovingienne, et confirmer le changement de recettes d’opacifiant/colorant dès le tout début de la période mérovingienne où l’utilisation d’oxydes d’étain ou de stannates de plomb est généralisée et celle des antimoniates complètement abandonnée. Enfin nous avons pu mettre en évidence l’utilisation d’un verre très riche en plomb pour la fabrication de perles noires dès le début de la période d’occupation du site, verre qui à notre connaissance n’a jamais été documenté [less ▲]

Detailed reference viewed: 39 (2 ULg)
See detailNeanderthals see red : production of red powder in the Late Mousterian in Ormesson, France
Salomon, Hélène ULg; Geurten, Stéphanie; Bodu, Pierre et al

Poster (2013, February 07)

Les Bossats, near Ormesson, is a newly discovered late Mousterian site dated around 47.000 B.P. by thermoluminescence. The archaeological level, fossilized by loess, revealed a rich industry based on the ... [more ▼]

Les Bossats, near Ormesson, is a newly discovered late Mousterian site dated around 47.000 B.P. by thermoluminescence. The archaeological level, fossilized by loess, revealed a rich industry based on the discoide mode, associated with numerous fragments of red iron-rich rocks. The geological sources were identified by means of SEM-EDX, XRD, Raman spectroscopy, PIXE and by petrographical observation of thin sections. The past mechanical and morphological modifications of the pigment blocks were characterized by macro-photography, microscopy and topographical micro- measures of the used surfaces. It was thus possible to demonstrate that the colouring materials were selected in the neighbouring by the Neanderthals. Fourteen blocks and fragments show different use wears such as facets, grooves and scars. The Neanderthals implemented numerous techniques in order to produce preferentially red powder. The archaeological remains reveal an organized and versatile processing sequence of red ferruginous materials. During the late Mousterian a great phenomenon in expansion in western Europe is remarkable by the much wider exploitation of mineral red and black materials corresponding to technical modifications and divers utilizations under development. [less ▲]

Detailed reference viewed: 97 (3 ULg)
Full Text
See detailGeochemistry and XRD to differentiate oolitic ironstone geological levels from Germany, Belgium and France and application to the archaeological artefacts
Salomon, Hélène ULg; Goemaere, Eric; Mathis, François ULg et al

Conference (2013, February 07)

Particle Induced X-ray Emission (PIXE) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) have largely demonstrated their capability to analyse trace elements for determining the ... [more ▼]

Particle Induced X-ray Emission (PIXE) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) have largely demonstrated their capability to analyse trace elements for determining the origin of archaeological materials. Trace elements can in fact be used as fingerprint of the geological origin and thus contribute to provenance investigations. This point is an important question for prehistoric studies, as it provides information on mobility, exchanges and interaction between groups of population. We present experimental PIXE configurations which allow to investigate prehistoric oolithic haematite, at the ppm level without any preparation or sampling. We compare the data obtained with two devices, namely AGLAE (Accélérateur Grand Louvre d'Analyse Elémentaire) in Paris and the cyclotron in the Centre Européen d'archéométrie in Liège and we determined the uncertainties of measures. The geological samples were compared in order to estimate de geochemical variability in stratigraphy and in width of oolithic haematite from the Ordovician in Caen region (France) and from the Devonian in Hesbaye (Belgium). These data were also compared to oolithic haematite used during Mesolithic and LBK (Early Neolithic) in both the regions. Furthermore we looked for mineralogical fingerprints by X-Ray Diffraction on disoriented powders. The mineralogical composition is ubiquitous and no discrimination between the stratigraphical layers was possible. [less ▲]

Detailed reference viewed: 54 (4 ULg)
See detailLe bol de Wellin et son "parent" de Valsgärde?
Van Wersch, Line ULg; Mathis, François ULg

in Lorren, Claude (Ed.) La Gaule, le monde insulaire et l'Europe du Nord au haut Moyen Age (2013)

Detailed reference viewed: 25 (0 ULg)
Peer Reviewed
See detailPIXE-PIGE analysis of early medieval window glass from the abbey of Stavelot
Van Wersch, Line ULg; Mathis, François ULg; Biron, Isabelle et al

Poster (2013)

From the 1 st century, glass found in northern Europe was made from a mix of sand and natron that had to be imported from eastern Mediterranean [1]. After the fall of the Roman Empire, glassmakers could ... [more ▼]

From the 1 st century, glass found in northern Europe was made from a mix of sand and natron that had to be imported from eastern Mediterranean [1]. After the fall of the Roman Empire, glassmakers could either recycle existing glass or continue to import material. Then, around the end of the 8 th century, the first testimonies of potash glass, made with sand and trees ashes, are attested [1]. This type of glass would then prevail but the reasons and mechanisms of its appearance remain beyond understanding. They could be linked to the development of architecture and the growing needs of window glass. Founded in the middle of the VII th century, the abbey of Stavelot was a first time ruined by Vikings in 881. In the destruction levels, hundreds fragments of window glass were found [2]. 34 fragments were analysed in PIXE-PIGE at the cyclotron of the Institute of Nuclear and Atomic Physics and of Spectrometry of the University of Liège. The results show coexistence of both natron and potash glass on the site, even in the same archaeological contexts. For the coloration, the recipes to obtain turquoise or amber glass were comparable to those known on other early medieval sites [3], but to make green potash glass the artisans have used to two types of recipes. This shows the need to carry on researches and analysis on early medieval window glass in order to understand its production techniques that are also at the origin of famous gothic stained glass [less ▲]

Detailed reference viewed: 20 (0 ULg)
Peer Reviewed
See detailSpecialized « ochre » procurement strategies in the Transition context : the red pigments from the Châtelperronian of the Grotte du Renne, Arcy-sur-Cure (France)
Salomon, Hélène ULg; Coquinot, Yvan; Beck, Lucile et al

Poster (2012, June 01)

In many reports of prehistoric pigment studies, these artefacts are considered as the testimony of past symbolic activities. The first step of the processing sequence, that is to say the acquisition of ... [more ▼]

In many reports of prehistoric pigment studies, these artefacts are considered as the testimony of past symbolic activities. The first step of the processing sequence, that is to say the acquisition of raw colouring material, is not well described and understood. Physico-chemical (SEM-EDS, XRD, TEM-EDX, µPIXE-µPIGE) and petrological analysis were carried out on the colouring materials excavated in the châtelperronian layers (40000-35000 B.P.) of the French site the Grotte du Renne in Arcy-sur-Cure. The Châtelperronian is one of the transitional techno-complexes, basically one of the last cultures made by Neanderthals in Europe. The physico-chemical data were related to the location of the colouring materials on the site, in association with exceptionally well preserved “hut” structures. It was thus possible to demonstrate that none of these materials, either red or black, was heated before being used, contrary to what had been assumed so far. The supply in colouring materials was as carefully organized as for mineral materials such as flint, for example; they were collected in different geological formations occasionally showing on the surface, close to the cave and at more than 30 km from the cave. The exploitation of these geological sites did not vary during the whole Châtelperronian period, and privileged materials which can easily be ground to powder. The set of colouring minerals from the Grotte du Renne reveals Neanderthals’ in-depth knowledge of mineral materials; they understood perfectly well their properties and qualities, and used them extensively, so that the raw colouring material was part of the livelihood and the Châtelperronian site must have been a literally dazzling sight, all red and black. [less ▲]

Detailed reference viewed: 63 (1 ULg)
See detailTiO2 templated multilayer films used as high efficiency photoelectrode in liquid or solid DSSCs
Dewalque, Jennifer ULg; Cloots, Rudi ULg; Mathis, François ULg et al

Conference (2012, April 10)

Mesoporous anatase thin films are very promising materials to act as electrode in dye-sensitized solar cells. Randomly oriented nanocrystalline TiO2 particles are usually used to prepare photoelectrodes ... [more ▼]

Mesoporous anatase thin films are very promising materials to act as electrode in dye-sensitized solar cells. Randomly oriented nanocrystalline TiO2 particles are usually used to prepare photoelectrodes with a thickness of 10-15 µm. Templated-assisted dip-coating techniques are used to obtain thin films with ordered porosity. However, monolayer films prepared by dip-coating from a solution suffer from a low quantity of active material with a limited surface area, leading to poor photovoltaic performances. Therefore a multilayer deposition process is needed to increase the film thickness along with surface area. Multilayer dip-coating procedures have already been reported but are usually characterized by a lack of linearity in the evolution of parameters (roughness, surface area, PV performances) as the number of layer increases. In this study, we investigate a dip-coating-based multilayer deposition technique delaying these limitations. First, the influence of the template on the film organization and porosity is studied in terms of long-range order, percentage of porosity, pore size, surface area and pores connectivity. Different techniques such as transmission electron microscopy (TEM), atmospheric poroellipsometry (AEP) and UV-visible absorption spectroscopy (UV-vis.) have been used to describe the microstructural features of the films. The film exhibiting the highest dye loading was selected and its thickness gradually increased up to 4 µm. Finally, the photovoltaic performances of the thick films (1 to 4 µm) have been evaluated in combination with the N719 dye and a liquid electrolyte and show excellent efficiency (6.1%) when compared to values reported in the literature. Such mesostructured films were compared in terms of photovoltaic performance with TiO2 nanoparticles films, generally used in DSSC. Films were further evaluated by Rutherford Backscattering Spectrometry (RBS) as high performance photoelectrode in solid-state DSSCs, in combination with Z907 dye and Spiro-OMeTAD as solid electrolyte. [less ▲]

Detailed reference viewed: 45 (12 ULg)
Full Text
Peer Reviewed
See detailNew external beam and particle detection set-up of Liège cyclotron – First applications of high energy beams to cultural heritage
Chene, Grégoire ULg; Bols, Stéphanie; Dupuis, Thomas ULg et al

in Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (2012), 273

Improvements on the Liége cyclotron have yielded an energy resolution comparable to that of classic electrostatic accelerators. The latest upgrades of the High-Energy High-Resolution beam line (HE-HR) are ... [more ▼]

Improvements on the Liége cyclotron have yielded an energy resolution comparable to that of classic electrostatic accelerators. The latest upgrades of the High-Energy High-Resolution beam line (HE-HR) are presented which consist of the addition of both a new extraction nozzle for non-invasive in-air measurements and a new particle-detection setup developed to take full advantage of the increased probed thickness with depth sensitive analytical methods. The suitability of the new setup and the advantages provided by the larger flexibility in choosing both the proper particle with an extended energy available will be illustrated by discussing latest results of studies recently led on Roman gilding techniques on cultural heritage artifacts by means of “High-Energy” alpha backscattering spectrometry combined with PIXE. [less ▲]

Detailed reference viewed: 28 (11 ULg)
Full Text
Peer Reviewed
See detailRutherford backscattering analysis of porous thin TiO2 films
Mayer, Matej; von Toussaint, Udo; Dewalque, Jennifer ULg et al

in Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (2012), 273

The additional energy spread due to sample porosity was implemented in the SIMNRA simulation code, version 6.60 and higher. Deviations of the path length and energy loss distributions from the ones ... [more ▼]

The additional energy spread due to sample porosity was implemented in the SIMNRA simulation code, version 6.60 and higher. Deviations of the path length and energy loss distributions from the ones expected from a Poisson distribution of the number of traversed pores are taken into account. These deviations are due to the interaction of pores at higher pore concentrations by overlap or blocking. The skewnesses of the energy distributions are approximated by two-piece normal distributions with identical first three moments. Propagation of porosity-induced energy spread in thick layers is taken into account. Calculated results are compared to experimental data obtained with thin TiO2 mesoporous films measured by Rutherford backscattering (RBS),transmission electron microscopy (TEM), and atmospheric poroellipsometry. [less ▲]

Detailed reference viewed: 77 (27 ULg)
Full Text
See detailLes lissoirs en verre médiévaux : Analyse de quelques exemplaires découverts en Wallonie
Vrielynck, Olivier; Mathis, François ULg

in Annales de la Société Archéologique de Namur (2012), 86

Detailed reference viewed: 13 (1 ULg)
Full Text
Peer Reviewed
See detailStudy of medieval glass fragments originating from Savona (Italy) and their relation with the glass produced in Altare
Cagno, Simone; Badano Borondi, M.; Mathis, François ULg et al

in Journal of Archaeological Science (2012), 39(7), 2191-2197

Altare was in the medieval and post-medieval period an important glassmaking center in the Liguria region in Northern Italy. The first historical evidence of glassmaking in Altare is dated to the twelfth ... [more ▼]

Altare was in the medieval and post-medieval period an important glassmaking center in the Liguria region in Northern Italy. The first historical evidence of glassmaking in Altare is dated to the twelfth century. In spite of that, due to the continuity of glassmaking up to the present time and the contemporaneous intensive urbanization of the territory, no medieval glass from Altare or its immediate vicinity has been analyzed up to now. In this work, glass from archaeological excavations in the center of Savona, city with close ties with the glassmaking center, was studied. Glass fragments, dated from the tenth to the sixteenth century were selected from the collections of the Archaeological Museum in Savona and non-destructively analyzed with quantitative PIXE-PIGE. The resulting compositions, compared with known glass productions of the same time and evaluated on the basis of historical documents, offer an interesting panorama on the variety of glass circulation in Liguria. [less ▲]

Detailed reference viewed: 41 (18 ULg)
Full Text
Peer Reviewed
See detailX-ray production cross-sections measurements for high-energy alpha particle beams: New dedicated set-up and first results with aluminum
Dupuis, Thomas ULg; Chene, Grégoire ULg; Mathis, François ULg et al

in Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (2011), 269(24), 29792983

The “IPNAS” laboratory, in collaboration with the “Centre Européen d’Archéométrie” is partly focused on material analysis by means of IBA techniques: PIXE, PIGE and RBS. A new transport beam line has been ... [more ▼]

The “IPNAS” laboratory, in collaboration with the “Centre Européen d’Archéométrie” is partly focused on material analysis by means of IBA techniques: PIXE, PIGE and RBS. A new transport beam line has been developed at our CGR-520 MeV cyclotron to analyze Cultural Heritage objects using these techniques. This facility allows us to produce proton and alpha particle beams with energies up to 20 MeV. A vacuum chamber dedicated to X-ray production and Non-Rutherford cross-section measurements has been recently constructed. After determination of the chamber’s geometry for X-ray detection using thin foils of several elements (11 ⩽ Z ⩽ 82) and 3 MeV proton beams, the measurement of the X-ray production cross-sections in the 6–12 MeV energy range has started using alpha particle beams on light element targets. These experiments contribute to the filling a serious lack of experimental values for alpha particles of this particular energy range in databases. The recent decision to focus our work on the alpha particle interaction with light elements was taken because of the high interest of the low Z elements in the field of archaeometry. [less ▲]

Detailed reference viewed: 18 (4 ULg)