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L’accélérateur de particules AGLAE du C2RMF a eu un rôle majeur dans l’émergence du projet européen Eu-ARTECH. Après un bref rappel des propriétés des méthodes d’analyse par faisceau d’ions, la spécificité d’AGLAE est soulignée. Les activités impliquant l’accès transnational (TNA) à cette installation sont alors présentées, révélant la grande diversité des thèmes scientifiques abordés. Des exemples d’études sont donnés, qui illustrent la contribution d’AGLAE à la connaissance des œuvres d’art et d’archéologie et tout particulièrement celles en céramique et en métal. C2RMF’s AGLAE ion beam accelerator has played a major role in the emergence of the European project Eu-ARTECH (Access, Research and Technology for the Conservation of the European Cultural Heritage). After a brief reminder of the properties of ion beam analysis, AGLAE’s specific characteristics are highlighted. Activities open to transnational access (TA) in this laboratory are then presented, attesting to the broad diversity of scientific subjects available to researchers. Examples of studies are given, illustrating AGLAE’s contribution to greater knowledge about works of art and archaeology, especially ceramics and metal artefacts.

The combination of particle-induced X-ray emission (PIXE) and Rutherford backscattering (RBS) is particularly fruitful for the study of cultural heritage objects. Several set-ups have been developed at the AGLAE facility of the Louvre Laboratory to implement these techniques with an external beam. Successively have been tested the simultaneous use of PIXE and RBS with a single beam of protons, the sequential application of PIXE with protons and RBS with 4He2+ ions and finally the simultaneous implementation of PIXE and RBS with high-energy 4He2+ ions. Several examples illustrate the benefits of these combinations of techniques.

The application of IBA to cultural heritage mostly relies on the use of PIXE because of its high sensitivity and its ease of implementation at atmospheric pressure. The need for depth information not easily available with this technique has conducted to associate RBS also in external beam mode. We have progressively developed a set-up that permits such a combination of techniques either simultaneously or sequentially. The set-up is currently further improved to permit NRA measurement (depth profiles of light elements) in addition to PIXE and RBS. The coupling of all these techniques provides a wealth of information on cultural heritage objects, not easily attainable with any other single method.

Ion beam induced luminescence (IBIL) has been used for studying the emission features and the radiation hardness of white pigments. In particular, ZnO, gypsum and basic lead sulphate pigments have been analyzed with a 3.0 MeV H+ beam at the AGLAE Louvre laboratory. The same pigments mixed with different binders have been also analyzed on a canvas, in order to evaluate the contribution of the binders both to the IBIL spectra and to the radiation hardness. It turns out that the binder affects both the IBIL spectra and the radiation hardness of pigments when the emission bands are related to point defects, as occurs for ZnO.

Many lead silicate historical glasses suffer degradation phenomena often observed as color changes and iridescence caused by lead ions leaching from the outer layers of the glass. In order to repair and to prevent these phenomena, glasses with large amounts of lead (6.7 and 14.3 at.% of lead) have been coated with silica films at neutral pH by dipping them in a precursor solution of TEOS (tetraethyl orthosilicate), ethyl alcohol and deionized water without any other acid or basic catalyst. Experiments with long dipping times (24 h) and temperatures around 20 °C have been performed to evaluate the role of lead ions of the glass as a catalyst. Silica films of very good quality and optical transparency have been also obtained on lead-free, soda-lime glasses by adding catalytic amounts of Pb(NO 3 ) 2 instead of HCl to the precursor solution. The films have been characterized by optical microscopy, AFM (Atomic Force Microscopy), XPS (X-ray Photoelectron Spectroscopy) and SIMS (Secondary Ion Mass Spectrometry).

This paper reports on the use of PIXE and RBS (resonant and non-resonant RBS) implemented with proton beams to simultaneously analyse light and heavy elements in materials of cultural heritage significance, as exemplified by Russian icons or in lead seals. It is shown that in spite of its poor mass resolution RBS with protons can provide useful information when combined with PIXE. In the case of Russian icons, it is possible to discriminate between an Au-Ag bilayer and an alloy of these metals in the gilds. However, when applied to lead seals RBS with protons encounters a significant limitation due to some deficiency in the available computer programs used for spectrum processing. (c) 2005 Elsevier B.V. All rights reserved.

Two paintings by Murillo from the Louvre Museum entitled Agony in the garden and Penitent St. Peter kneeling before Christ and the column were analysed by PIXE to identify the nature of their unusual dark mineral backing. Considered until now as black marble, this support turns out to be obsidian, with an almost identical elemental composition for the two works. This composition was compared to that of six Mesoamerican unpainted obsidians labelled “ smoking mirrors ” with comparable size and shape from the Paris Museum National d’Histoire Naturelle and Musee de l’Homme and to that of geological samples from five Mexican sources. The trace element contents of Murillo’s obsidians, in particular those of Mn, Zr, Sr, Y, Rb, Zr, Nb and Zn appeared to be very similar to that of four smoking mirrors and to that of obsidians from the Ucareo-Zinapecuaro source in central Mexico, an important complex of obsidian quarries exploited since pre-Hispanic times. A literature survey showed no such similarity with obsidians from other Mesoamerican sources or even from Mediterranean and surroundings source-areas. This study points out that Murillo, although living in Sevilla, had occasionally employed for his paintings materials shipped from the New World to Spain.

For 30 years analytical methods based on ion beams have been progressively adapted to art and archaeological issues. By allowing the analysis of artefacts in a non-invasive and non-destructive way, the external beam represents the cornerstone of this evolution. In order to reach in air specifications usually obtained under vacuum, improvements in various directions have been necessary. A large panel of gadgets and experimental arrangements have been designed such as a multi-detector set-up operating in helium atmosphere to extend the range of measured elements, a nuclear microprobe at atmospheric pressure for the study of microscopic details or a reliable beam monitoring system. In addition, specific procedures have been developed to characterise multi-layered samples (easel paintings, alteration layers) by varying either the beam energy or the impinging angle. To improve the sensitivity to trace elements in high-Z materials like metals or for analysing targets too sensitive to stand direct exposure to charged particles, a specific X-ray fluorescence set-up (PIXE-XRF) based on the production of quasi-monochromatic X-rays has been developed. Eventually, the ion beam methods usually restricted for external beams to those based on photon detection (PIXE, PIGE) have been recently extended to methods based on charged particle detection (RBS, NRA and even ERDA), opening new perspectives for determination of light elements and depth profiling. This paper makes an historical review of the adaptation of IBA methods to the study of cultural heritage.

An open-air furnace has been designed to study in real time the high-temperature surface transformation of materials by Rutherford backscattering spectrometry (RBS) in external beam mode. A device previously designed for the observation of the high-temperature oxidation of galena has been re-designed in order to analyse massive samples and to reach a temperature range up to 700 °C and a better temperature regulation (±2 °C). Experiments are carried out to measure, by RBS using a 3 MeV 4 He 2+ external micro-beam, the dynamic growth of oxide layers in air on the surface of copper–tin alloys heated at temperatures varying from 250 to 650 °C. The results obtained demonstrate the usefulness of this approach: actually one single measurement series permits to obtain at the same time the composition of oxide layers built on the metal and their growth kinetic laws. In the particular study of bronzes, the growth kinetics obtained by this method show the large influence of tin concentration on the oxidation mechanism. These results are verified by measurements on samples oxidised in an independent closed furnace. The results show also the occurrence of different oxidation mechanisms as a function of temperature. A diffusion mechanism governs the oxidation kinetics only at some temperatures.

For several years, we carry out a research on metalpoint drawings, a graphic technique mainly employed by European artists during the 15th and 16th centuries. As a non-destructive and very sensitive analytical technique is required, particle induced X-ray emission (PIXE) analysis with an external beam has been used for this purpose. More than 70 artworks drawn by Italian, Flemish and German artists have been analysed, including leadpoint and silverpoint drawings. Following a short description of the metalpoint technique, the results are compared with the recipes written by Cennino Cennini at the beginning of the 15th century and specific examples are presented.

Elemental analysis by X-ray fluorescence and particle induced X-ray emission is applied to the study of several Mesoamerican mural samples containing blue pigments. The most characteristic blue pigment is Maya blue, a very stable organo-clay complex original from Maya culture and widely used in murals, pottery and sculptures in a vast region of Mesoamerica during the pre-hispanic time (from VIII century) and during the colonization until 1580. The mural samples come from six different archaeological sites (four pre-hispanic and two from XVI century colonial convents). The correlation between the presence of some elements and the pigment colour is discussed. From the comparative study of the elemental concentration, some conclusions are drawn on the nature of the pigments and the technology used.

For more than 14 years, an IBA facility has been operated in the Louvre for the study of works of art and archaeology. The choice of this equipment derives from the non-destructive character of IBA techniques which has been further strengthened by designing an external beam line permitting the in-air analysis of large or fragile works of art without sampling. Successive improvements have markedly extended the analytical capability of the set-up. The measurements were originally restricted to PIXE–PIGE combination using an external millimetre-sized-beam. By adding a focusing system and an ultra-thin exit window we were able to obtain external beams of protons and alpha particles of respectively 10 and 50 μm in diameter, with low energy straggling. These features have permitted to apply in external beam mode other IBA techniques including RBS, NRA and more recently ERDA. Moreover, elemental maps can be drawn in PIXE and PIGE modes by mechanically scanning the sample under the fixed beam within a lateral range much larger than conventional nuclear microprobes. This facility is used for both short investigations at the request of museum curators and extensive research works in art history and archaeology. Several examples are given to highlight the impact of this tool on cultural heritage.

Painting glazes, which are coloured translucent layers used in oil paintings, show evidence of pigment migration upon examination of cross sections with optical microscope and scanning electron microscope (SEM). The present work deals with the use of two complementary accelerator-based analytical techniques, Particle Induced X-ray Emission (PIXE) and Rutherford Back-scattering Spectrometry (RBS), to tentatively reveal such a phenomenon in a non destructive way on experimental glazes. These glazes were prepared by successive addition of layers of emerald green pigment dispersed in a linseed oil medium and having the same pigment content. They were then analysed by PIXE and RBS to provide respectively the bulk elemental composition and the depth distribution on the same spot. It is shown that the pigment concentration at the surface increases with the number of layers up to a saturation value, thus revealing the pigment migration toward the surface.

Accelerator-based analytical techniques using external beams are ideally fitted to the study of works of art because of their fully non-destructive character. However, accurate quantitative analysis is not straightforward, due in particular to difficult beam monitoring. Significant improvements have been progressively made on the external beam line of the IBA facility of the Louvre museum in order to increase the accuracy and to conduct combined analyses with different IBA techniques.

This paper reports a study of colours and inks of an ancient Egyptian papyrus using an external proton microprobe in PIXE mode. Representing the Book of the Dead, this papyrus is dated from the 19th dynasty, New Kingdom (c.1295–1186 BC). Elemental maps were obtained by moving the papyrus under a fixed focused external beam using a motorised support. The maps were compared to photographic pictures taken in visible light. Inks used in the hieroglyph text appeared to be based on carbon (black) and iron oxide (red). Coloured drawings illustrating the text showed a wider palette: hematite, ochre, orpiment, Egyptian blue, verdigris. Most intriguing was the observation in several parts of the drawing of a whitish pigment containing strontium. Deposits of strontium-rich minerals (e.g. strontianite, celestite) have been identified in Egypt. The exact nature and the archaeological implications of this pigment have still to be determined. Finally, fine powder and coarse grains of arsenic oxide were observed, probably remaining from an early preservation treatment against insect attacks after excavation.

Proton-induced X-ray emission (PIXE) mapping and PIXE spot analysis have been performed on three original manuscripts. We observed that the precision of the spot measurements for the analysis of the ink composition is limited by the heterogeneity of the writing. PIXE mapping proved to be a complementary technique which is much more sensitive, and which makes it possible to evaluate the migration of some elements, such as sulphur, iron and calcium around inscriptions.

In situ RBS measurements with an external He ion micro-beam have been performed on galena heated at temperatures varying from 400°C to 600°C, to study dynamically its oxidation kinetics. At each temperature, a millimetre-sized crystal is placed in a specially built oven directly facing the exit window of the beam. The thickness of the oxidised layer is measured every 2 min by means of the lead signal in the RBS spectrum, using a 3 MeV 4 He 2+ external focused beam (about 100 μm). We infer the diffusion mechanism from the growth of a phase, which is more or less stable when increasing temperature. This probing beam allows one to characterise layers of thickness extending from about 100–2000 nm.

The external beam line of our facility has been recently equipped with the focusing system previously mounted on a classical nuclear microprobe. When using a 0.1 μm thick Si3N4 foil for the exit window and flowing helium on the sample under analysis, a beam spot as small as 10 μm is attainable at a distance of 3 mm from the window. Elemental micromapping is performed by mechanical scanning. An electronic device has been designed which allows XY scanning by moving the sample under the beam by steps down to 0.1 μm. Beam monitoring is carried out by means of the weak X-ray signal emitted by the exit foil and detected by a specially designed Si(Li) detector cooled by Peltier effect. The characteristics of external beams of protons and alpha particles are evaluated by means of resonance scanning and elemental mapping of a grid. An example of application is presented, dealing with elemental micro-mapping of inclusions in gemstones.

A large collection of emeralds of various occurrences has been analysed by PIXE/PIGE in view to establish a compositional database. Major elements (Be, Si, Al) and trace elements (Li, F, Na, Mg, Ca, Rb, Cs and transition metals) are determined using an external 3 MeV proton micro-beam. Elemental micro-mapping permits to select the useful provenance tracers. This database was applied to infer the origin of several ancient emeralds set on historical jewels.

Combined RBS and NRA measurements at atmospheric pressure have been performed on copper alloys of archaeological significance with external beams of, respectively, 3-MeV protons and 2-MeV deuterons. The objective is to determine the structure and composition of the patina through the depth profiles of the constituent elements, particularly C, N, O, obtained by (d,p) nuclear reactions. An iterative fitting procedure of both RBS and NRA spectra permits to reach this goal with a high degree of confidence. ” 2000 Published by Elsevier Science B.V. All rights reserved.

The properties of fluorapatite, both a useful radiochronometer and a potential storage matrix specific for minor actinides produced by the reprocessing of spent nuclear fuel, have been investigated with emphasis to its response to alpha decay. Exfoliation, which occurs after implantation of high doses of 1.6-MeV He-ions (>1.4×10 17 ions cm −2 , corresponding to 5% atomic proportion), could set an upper limit to the concentration of imbedded actinides (about 2 atoms % corresponding to 20 wt. %) or storage age unless significant diffusion of radiogenic He intervenes. This process has been studied by combining He implantation, thermal treatments in the temperature range 124–250°C and measurement of the resulting He profile by an ion beam technique (ERDA) using 8.5-MeV C ions. The diffusion coefficient follows an Arrhenius' law with an activation energy of 120 (±2) KJ/mole and a frequency factor of 14.5 (±7)×10 −3 cm 2 sec −1 in agreement with literature data. The inferred closure temperature which validates the U,Th–He radiochronological method also fits previous values: 97 (±10)°C for grain size 165 μm. With respect to radwaste disposal. He volume diffusion is too small to exclude the occurrence of exfoliation unless diffusion at grain boundary is much higher and a fine-grain matrix is deliberately chosen.

External beam lines have been built on numerous IBA facilities for the analysis of works of art to avoid sampling and vacuum potentially detrimental to the integrity of such precious objects. On the other hand, growing interest lies on microprobe systems which provide a high lateral resolution but which usually work under vacuum. Until recently, the AGLAE facility was equipped with separate external beam and microprobe lines. The need of a better spatial resolution in the external beam mode has led us to combine them into a single system which exhibits numerous advantages and allows the analysis of small heterogeneities like inclusions in gemstones or tiny components of composite samples. The triplet of quadrupole lenses bought from Oxford is used to focus the beam. By using a 0.75 μm thick Al foil as the exit window, blowing a helium flow around the beam spot and reducing the window-sample distance below 3 mm, a beam size of about 30 μm can be reached. The experimental setup includes two Si(Li), a HPGe and a Si surface barrier detectors for the simultaneous implementation of PIXE, NRA and RBS. The full description of this device is given as well as a few applications to highlight its capability.

This paper presents a study of the influence of swift-heavy-ion irradiation on the behavior of UO 2 towards aqueous corrosion. Single crystals of various orientations are irradiated with 340-MeV Xe ions and subsequently leached in deionized water at 180°C. The channeling technique is used to quantify the structural modifications induced by both irradiation and leaching. The U and O sublattices are investigated with standard Rutherford Backscattering (RBS) and the resonant scattering on 16 O at 3.045 MeV. Channeling angular scans are reproduced with Monte Carlo simulations. Irradiation induces a polygonization of the fluorite structure. Leaching leads to an incorporation of additional O atoms in the surface region of the UO 2 crystal which form a U 4 O 9 -like structure.

Archaeological flint tools exhibit, after their use, a modification of the orginal surface as a result of contact with foreign materials. The polish which appears, displays morphological and textural features characteristic of the worked material. These changes at the flint surface are mainly due to residues of the worked matter and therefore contain potential information on the tool use. However it is not clear whether the altered surface stems from a simple coating of soft matter which has filled the original roughness of the cutting edge or whether in addition to that process an erosion of the flint surface by loss of quartz spherules also occurs. An experimental study has been performed to address this issue, which is based on the implantation of Cu ions (energy 100 keV and a dose of 5 × 10 16 cm −2 ) on chipped geological flint samples, mechanical tests simulating the tool use and subsequent PIXE analysis of the edge surface with a 3 MeV proton micro-beam with a rectangular shape (15 × 20 μ m 2 ). A beam current of about 1 nA is sufficient to obtain a count rate of 800/min on the Cu Kα X-ray line. The persistence of the Cu X-ray signal all over the tool edge confirms that the polish is only due to the deposit of external matter. Archaeological implications of usewear are discussed in the light of these new data.

The build-up of the oxide layer on austenitic steel under boiling water reactor (BWR) conditions was studied by macro- and micro-Rutherford backscattering spectrometry (RBS) and sputtered neutral mass spectroscopy (SNMS). RBS is applicable when the oxide thickness is larger than 20 nm and yields both the layer thickness and its stoichiometry. SNMS provides elemental depth profiles and the oxide thickness when combined with profilometry. Stainless steel strip samples pre-treated (electro- or mechanically polished) or not, exposed in a loop simulating the BWR-conditions for periods ranging from 31 to 291 days and with a low water flow velocity show oxide layers with a thickness of about 300 to 600 nm. There is no significant increase of the oxide layer thickness after 31 days of exposure. The paper confirms the presence of inner and outer oxide layers and also confirms the stoichiometry M2O3 in the external part in contact with the oxygenated water. The oxide layer consists not only of an outer layer and an inner layer but also of a deep apparent oxide/metal interface that is attributed to oxide formation through the steel grain boundaries.

An extensive knowledge of radiation damage in nuclear fuel elements is of considerable importance for technological applications. Ion bombardment and ion-beam analysis techniques provide efficient tools in order to simulate and characterize the structural modifications induced by irradiation. This paper deals with the study of radiation effects induced in UO 2 single crystals irradiated with 340-MeV Xe ions which simulate high electronic excitations sensed by the nuclear fuel during the slowing-down of fission fragments. Radiation damage was characterized by the RBS-channeling techniques. Resonant scattering 16 O( 4 He, 4 He) 16 O occurring at 3.045 MeV was applied to the study of oxygen sublattice modifications. A strong disordering of both U and O sublattices was observed, even at very low ion irradiation fluence (∼ 10 13 cm −2 ).

Samples of albite feldspar were dissolved at 300C and 170 bars for periods up to 24 h in flow-through reactors at acid, neutral, and basic pH conditions. Three MeV ion beam techniques, Resonant Nuclear Reaction Analysis (RNRA), Rutherford Backscattering Spectrometry (RBS), and Elastic Recoil Detection Analysis (ERDA) were employed to obtain elemental depth profiles and information on the composition of the near-surface region after dissolution. Based on the anti-correlative trends of the H and Na profiles obtained by RNRA, Na loss and H permeation are coupled by an ion exchange process in acidic and neutral pH solutions. At basic pH conditions, the evidence is ambiguous as to whether there is a limited degree of ion exchange between aqueous cations and Na, as based on RBS spectra and Na RNRA profiles. The recorded depths of H permeation and Na leaching range from a maximum at acid pH (H permeation exceeding ∼10,000A, Na leaching ∼20,000A) to a minimum at basic pH (no H enrichment, Na leaching depths of several hundredA). The composition of the leached/H-enriched region is a function of pH. This is postulated to be primarily a function of two factors: the H ion concentration gradient between the solution and the solid, which directly controls the pH-dependence of the ion exchange couple H+ (or H3O+) ← Na+ and secondly, the speciation of Al -OH and t.sbnd; Si -OH groups created by hydrolysis reactions and the subsequent preferential release of Al within the leached/H-enriched zone. Based on the ratios of H uptake to Na loss at acid and neutral pH, which range between 0.7 and 2.5, it is not possible to distinguish between H+, H2O, and H3O+ species permeating into the structure. Free water may be created within the leached/ H-enriched structure via recondensation (repolymerization) reactions of adjacent Si&-OH groups. Excess H concentration profiles potentially provide indirect evidence for recondensation reactions at depths

Surface layers on the French borosilicate nuclear waste glass, R7T7, corroded in MgCl2 solution were studied to determine the composition, structure and stability of crystalline phases. The characteristics of the phases constituting the surface layer varied with the parameter SV × t, the glass surface area (S) to solution volume (V) ratio, times time (t). At low SV × t values ( 98% of the neodymium released from the glass were precipitated in the surface layer. In the 463 day experiment, 86% of the neodymium in the surface layer was in solid solution with powellite, the rest with saponite. Uranium was contained exclusively in saponite. High SV ratios, typical of disposal conditions for vitrified high-level radioactive waste, favor retention of actinides in fairly insoluble corrosion products. Observation of similar corrosion products on natural glasses as on nuclear waste glasses lend support to the hypothesis that the host phases for actinides observed in the laboratory are stable over geological periods of time.

For three decades, ion beam analysis (IBA) in external mode was considered as the best choice for the characterisation of cultural heritage materials, as it combines excellent analytical performance and non-invasive character. However, in recent years, other analytical techniques arose as serious competitors, such as those based on synchrotron radiation (X-ray absorption, fluorescence or diffraction) or those using portable instruments (XRF, micro-Raman). It is shown that nevertheless IBA remains unmatched thanks to two unique features, namely the analysis of light elements and the high-resolution 3D chemical imaging.

The atomic transport induced by ion electronic energy loss in amorphous systems is studied on metallic sandwiches irradiated at liquid nitrogen temperature with 500 MeV iodide ions delivered by the VICKSI accelerator of the Hahn-Meitner-Institut (Berlin). The sandwiches are composed of two amorphous Ni3B layers of 1 or 1.5 μm thickness embedding a crystalline Au or W layer of thickness varying from 20 to 900 nm. Rutherford backscattering experiments using a 3.6 MeV He2+ beam delivered by the ARAMIS accelerator of the CSNSM (Orsay) were performed in order to determine the modifications of the geometry of the sandwiches after swift heavy ion irradiation. The results show a huge creep of the crystalline part of the sandwiches. The magnitude of this creep depends on the nature of the crystalline layer (Au or W) and increases steadily with the irradiating ion fluence with a strain-rate decreasing with increasing layer thickness. This creep phenomenon is due to the plastic deformation process occurring in the surrounding amorphous layers and is induced by ion electronic energy loss. A simple rheological model is developed to reproduce the observed effects.

The macroscopic atomic transport induced in amorphous systems by ion electronic energy loss is studied by means of RBS experiments on a marker either implanted (Bi) or evaporated (Au) in the target. Irradiation of amorphous Ni3B with 500 MeV I ions leads to (i) a huge shift of the marker profile towards the sample surface, (ii) a surprising decrease of its distribution width. The results are totally accounted for by the plastic deformation phenomenon induced by electronic excitation in amorphous materials.

The aqueous corrosion of a series of four glasses under static conditions at 65 and 90°C was studied by means of solid and solution analyses. Various glass compositions were studied by successive addition of Al2O3, CaO and Fe2O3 to a simple sodium borosilicate glass in order to maintain a compositional and structural analogy to a simulated high-level radioactive waste glass. The comparison of leaching behaviours shows that Al has the greatest influence on the chemical durability, probably for two main reasons: (i) a structural effect on the glass network and on the compound forming the residual alteration layer (ii) a solubility constraint on the residual layer. The identification of the phase composing the alteration layer was only possible for the simplest glass. On the basis of chemical analysis, infrared spectroscopy and solubility constraints, it was identified as amorphous silica. For the other glasses, the alteration process led to the growth of an alteration layer made up of an amorphous hydroaluminosilicate. This material cannot be defined as a phase with a fixed chemical composition ad known thermodynamic properties. The chemical composition of this compound, initially controled by the glass composition, adapts to changes in the solution chemistry, especially pH.

To understand the mechanism underlying fluorination of buried archaeological flints, samples of amorphous silica have been subjected to fluorine incorporation either by aqueous treatment or by ion implantation. The nuclear reaction analysis technique using the resonant 19F(p, αγ)16O reaction at 872 keV has been used to obtain profiles of fluorine with an automated electrostatic energy scanning system. Our results emphasize the role of defects for F uptake and allow us to propose a tentative mechanism for F diffusion. The use of synthetic hydrated silica appears promising to simulate the geochemical weathering of chalcedony.

The German nuclear waste glass GP 98 12 was implanted with Kr ions at different temperatures up to 350 °C. thus covering and extending the temperature range expected in a repository for fully radioactive nuclear waste glasses. Vickers indentations were used to measure the fracture toughness, KIc, leaching was done at different temperatures up to 200°C in deionized water, and the leached surfaces were analyzed by RBS and ERDA in order to determine the changes in composition connected with the formation of hydrated layers. For implantation at room temperature,KIc increased with the ion dose with a maximum at ∼ 5 × 1015ions/cm2. Such a dose corresponds to damage levels that will not be surpassed in real waste glasses. This technologically positive feature of damage was largely absent for implantation at T ⩾ 250°C, indicating that damage-induced stresses are significantly decreased for these conditions. In contrast, damage-induced enhanced leaching and hydration were observed also at higher implantation temperatures showing that the damage features responsible for increased leaching recover at much higher temperatures than those responsible for increased fracture toughness. This previously unknown difference is discussed in the context of related work on glasses using other damage sources (e.g. α-decay of incorporated short-lived actinides).

Ion beam induced luminescence (IBIL) has been exploited for the first time in the analysis of inorganic painting pigments. The elemental constituents of the different compounds have been determined by particle induced X-ray emission (PIXE). The acquisition time of each spectrum ranges from 100 ms to a few seconds, depending on the luminescence intensity. The luminescence features are fingerprints of the different compounds, thus identifying the provenience of pigments of the same nominal composition. Organic varnish layers do not affect the IBIL features, allowing the identification of pigments, like lapis-lazuli, whose identification with PIXE is hindered by the varnish. IBIL proved to be a technique complementary to PIXE in the archeometry and cultural heritage analysis fields.

Elemental composition fingerprinting by PIXE technique is very attractive for obsidian provenance studies as it may proceed in a non-destructive mode, even if a more complete elemental characterization can be obtained by ICP-MS and/or ICP-AES. Only few studies have compared results obtained by both methods for solid rock samples. In this work, elemental compositions were determined by ICP-MS/-AES for international geochemical standards and by ICP-MS/-AES and PIXE for inter-laboratory reference obsidians. In addition 49 obsidian source samples and artefacts were analysed by both ICP-MS/-AES and PIXE. Instrumental work and measurement quality control performed for obsidian chemical characterization, underline that PIXE and ICP-MS/-AES provide reproducible, accurate and comparable measurements. In some volcanic districts the limited number of elements dosed by PIXE is sufficient for the discrimination of the potential raw sources of obsidians. Therefore, PIXE can be an advantageous substitute to ICP-MS/-AES techniques for provenance studies.

International audience; The possibility of non-destructive elemental analysis makes PIXE a very attractive technique in archaeological provenance studies. This technique has been fruitfully implemented on two different facilities to address the issue of obsidian provenance in the Mediterranean and in surrounding regions. At C2RMF, we took advantage of the possibility to analyze large archaeological pieces with the external micro-beam set-up. At CENBG, we used the nuclear microprobe providing a 5 μm beam diameter in large scans (700 × 700 μm2) to control the homogeneity of elemental distribution. In both cases we dosed the same set of 13 elements: Na, Al, Si, K, Ca, Ti, Mn, Fe, Zn, Ga, Rb, Sr and Zr. While at C2RMF, two Si(Li) detectors were used simultaneously to measure all elements at once with 3 MeV protons, at CENBG where only one detector was available, the light elements Na to Fe were determined with a 1.5 MeV beam, and the heavy ones, including Fe, with a beam energy of 2.7 MeV. In Western Mediterranean, it is possible with PIXE to differentiate all obsidian sources of archaeological significance. Examples are given of obsidian provenances from Neolithic sites of France and from the islands of Corsica and Sardinia. In the Near East, we can differentiate the Cappadocian and Eastern Anatolian obsidian sources used during the early Neolithic. This is illustrated by examples taken from Neolithic sites of the Middle Euphrates Valley (Syria).

Lead silicate glasses (45.3 weight % of lead oxide) were leached in aqueous static solutions of HNO3 at pH=2 and T=90 °C for different leaching times, to study the weathering mechanism of lead glasses in an acidic environment. The leached surface was analysed by different analytical techniques like RBS (Rutherford backscattering spectrometry), XPS (X-ray photoelectron spectroscopy) and SEM-EDS (scanning electron microscopy-energy dispersive spectrometry). Even the leaching solutions were analysed by ICP-AES (inductively coupled plasma-atomic emission spectroscopy) to measure the amount of lead and other ions that migrate from the glass to the solution. The results obtained show that the leached layer, depleted of lead and alkaline ions, is some hundreds of nanometres thick. It is about ten times thinner than the one obtained on richer glasses (66 weight % of lead oxide), but the kinetics of the leaching process is exactly the same: a stabilisation takes place after two days of leaching and a Pb-enriched surface thin layer (a few nanometres thick) is formed.

L'analyse elementaire d'objets d'art ou d'archeologie exige l'emploi de methodes non destructives possedant une sensibilite suffisante pour les elements traces. La methode PIXE (acronyme pour Particle Induced X-ray Emission) satisfait a cette condition tout en se heurtant a deux contraintes majeures: le risque de deterioration de materiaux sensibles tels que les materiaux organiques et la faible sensibilite pour l'analyse d'impuretes legeres dans les matrices lourdes. Nous avons developpe une nouvelle ligne experimentale sur l'accelerateur de particules du Centre de recherche et de restauration des musees de France, permettant de s'affranchir de ces deux limitations en recourant a une variante de la fluorescence des rayons X, denommee PIXE-XRF (XRF pour X-Ray Fluorescence). L'extraction a l'air du faisceau permet une souplesse du dispositif nettement amelioree.

Non-conventional applications of IBA techniques are under development on an external micro-beam line dedicated to the study of materials relevant to cultural heritage. Special set-ups have been designed to investigate the kinetics of materials transformation by dynamic (real-time) analysis using either RBS or PIXE. The first technique is well fitted to the study of the thermal oxidation of solids in air, whereas the second one is suitable for measuring the rate of elemental release in the liquid phase during solid–solution interaction. Preliminary tests have been performed to demonstrate the usefulness of this approach. On one hand we have applied dynamic micro-RBS to study the oxidation kinetics at 360 °C of pure copper and a copper–gold alloy and on the other hand we have checked the ability of micro-PIXE to measure in real time the release of lead in solution during the aqueous dissolution of lead containing glass or glaze.

International audience; Using PIXE, we measured the chemical composition of 142 obsidian artefacts from 45 prehispanic archaeological sites and 22 obsidian samples from seven geological occurrences from Colombia and Ecuador. From PIXE data, these 164 samples may be classified into five chemical groups. Two source samples and a selection of 41 artefacts were dated by fission tracks. Some artefacts belonging to a single chemical group may have different formation ages and, hence, come from different sources. This results, for these 41 artefacts, in a minimum of eight sources, of which only three are identified. These are the Rı́o Hondo (Colombia), Mullumica and Quiscatola-Yanaurcu (Ecuador) sources. More than half (22) of the artefacts dated by fission tracks pertain to a single 0·25–0·30 Ma, age/composition group related to an unknown source. These artefacts were found essentially in archaeological sites (four in Colombia, 12 in Ecuador) of the Regional Development Period situated along the Pacific coast.

International audience; In the present work we have coupled PIXE with fission track dating to characterise obsidian artefacts from about 40 archaeological sites of Colombia and Ecuador. PIXE analysis, carried out with the external beam line of the AGLAE tandem accelerator, yields the content in about 15 elements with Z > 8, whereas fission track dating is applied to ages in excess of about 10 000 years. About 120 artefacts were investigated by PIXE, of which 50 were dated by fission tracks. Ages and compositions were compared to those of obsidians from all known geological sources of the region. We show that this double characterisation allows us to determine the number of obsidian sources exploited in an ancient past and to give some insight into obsidian circulation.

In order to study the behaviour of fluorapatite towards irradiation due to incorporated alpha-emitters, single crystals of this mineral have been bombarded with 220 keV Pb ions, simulating alpha recoil nuclei, and subsequently irradiated with He ions. The defect concentration measured by RBS associated with channeling steadily decreases upon He-ion irradiation. By changing the energy of the incident He ions in the range 0.3–3.2 MeV, we have shown that this defect annealing phenomenon can be ascribed to the electronic energy loss, while the use of B ions which have slightly higher electronic energy loss in the target induces the opposite effect, i.e., increases the defect concentration.

The scenario of spent fuel direct storage in a deep geological repository is currently under consideration in many countries. In this approach the nuclear fuel — mainly uranium dioxide —acts as a first barrier towards fission fragment and actinide release. Although the access of water in such a repository is rather unlikely, evaluating the safety of a disposal requires the knowledge of the mechanisms and kinetics of alteration and dissolution of the nuclear fuel in groundwaters. Despite the fact that the reported litterature on the topic is really extensive, it is still a challenging problem due to the complexity of the system: the used nuclear fuel cannot identify with uranium dioxide itself due to both radiation damage and modification of the matrix composition during reactor operation. Parametric studies in well-defined conditions on simple systems are therefore of prime importance in order to determine the relevant parameters involved in the structural transformations of the uranium-oxygen-water systenL The aim of the present work was to study the incidence of the electronic stopping of fission fragments on the behavior of nuclear fuel towards leaching in deionized water under oxidative conditions. Several features were of special interest: (i) quantification of the damage induced by swift-heavy ion irradiation prior to aqueous corrosion; (ii) stoichiometry and oxygen depth concentration of the alterated surface region; (iii) structural transformation of the crystalline structure induced by incorporation of additional O atoms; (iv) comparison between unirradiated and irradiated samples

The presence of metallic nanoclusters in an insulating matrix leads to non-linear optical properties with potential applications in optoelectronics. Ion implantation is currently used to produce such a composite material with limitations inherent to the implantation process, particularly concerning the doped thickness and the homogeneity of the transformed layer. Here we show that high-energy ion-beam mixing can be applied as an alternative ion beam technique to form metallic nanoclusters without the drawbacks of direct ion implantation. Thin SiO 2 -metal multilayers were irradiated at room temperature with MeV heavy ions in order to produce an homogeneous SiO 2 layer containing metallic nanoclusters over the whole sample thickness. The present works deals with the mechanism leading to the formation of metallic nanophases by ion-beam mixing.