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Microsonde électronique JEOL JXA-8230
La nouvelle microsonde électronique JEOL JXA-8230 de cinquième génération est un outil analytique puissant permettant une analyse chimique quantitative in situ et non destructive de matériaux solides polis. Cet équipement permet également d’obtenir des images électroniques et des images X de hautes résolutions montrant la distribution spatiale des éléments.
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| Cadre d’utilisation | Appareil utilisé pour de très nombreux projets scientifiques (ISTerre, OSUG, France, collaborations internationales) |
| Capacité d’analyse
– Voir détails |
.Analyse quantitative des éléments majeurs et mineurs à partir de 5B jusqu’à 92U avec témoins (Voir détails) . Analyse semi-quantitative et qualitative des éléments par EDS et WDS . Cartographie X semi-quantitative EDS/WDS . Imagerie en électrons rétrodiffusés et secondaires (BSE, SEI) . Imagerie en cathodoluminescence |
| Caractéristiques techniques
– Voir détails |
. 5 spectromètres WDS ; . Spectromètre EDS ; . W-source d’électrons ; . Tension d’acélération 0,2 à 30 kV ; . Gamme de courant 10-12 à 10-5 A ; . Stabilité de courant : +- 0,05%/h, +- 0,3%/12h ; . Résolution de l’image SEI : 6nm |
| Caractéristiques et préparation d’échantillons
– Voir détails |
Les échantillons doivent êtres solides et présenter un état de surface parfaitement plan. Voir les équipements pour la préparation d’échantillons |
| Responsable de l’outil et équipe associée
– Voir détails et tarifs |
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**ISTerre Electron Probe Microanalysis Facility
Electron-probe microanalysis is performed on our new JEOL JXA-8230 electron microprobe, which was purchased by the project ANR (Chair of Excellence ANR-09-CEXC-003-01 to A. Sobolev).
The Electron Probe X-ray Microanalyzer (EMPA), is a powerful analytical tool that provides non-destructive, in-situ and complete quantitative chemical analysis of a flat solid surface. It also provides high-resolution scanning electron and elemental X-ray images (map analysis) showing spatial distribution of elements.
Our JEOL JX-8230 is equipped with :
– Five wavelength dispersive spectrometers (WDS) providing quantitative analysis of elements from 5B – 92U. We have a large standard collection for analysis of most elements
– Energy dispersive spectrometer - a silicon-drift detector (SDD) for quick qualitative analysis . The SDD does not require cooling by liquid nitrogen.
– The WDS and EDS, or combined WDS/EDS can be used to obtain X-ray maps showing elemental distributions.
– Back-scattered electron detector for high resolution compositional (COMPO and TOPO) imaging.
– Secondary electron detector for high resolution morphological (SEI) imaging.
– Cathodoluminescence system for geological mineral screening.
– Specimen navigator system including flat scanner to produce digital sample map and positioning of analytical points.
ISTerre JEOL JXA-8230 : the combination of X-ray spectrometer, analyzing crystal and X-ray detector
Here is the list of elements that each crystal can be used to detect. Our probe equipped with new L-type spectrometer with too crystals PETL, LIFL. PETL to resolve trace element overlaps such as Pb-U-Th. LIFL useful for resolving minor peaks such as rare earth elements.
Electron optical system specifications :
W- electron source
Acceleration voltage : 0.2 to 30 kV
Specimen current : 10-12 to 10-5 A
Beam current stability : ±0.05% / h, ±0.3% / 12h
Resolution in SE image : 6 nm
Magnification : x40 to x300,000
X-ray detection system (WDS)
– Full quantitative analysis of major and minor elements
– Qualitative analysis of elements by EDS and WDS
– Elemental distribution maps and quantitative maps (by EDS and WDS or combined EDS/WDS)
– Backscattered electron imaging (BSE)
– Secondary electron imaging
– Cathode-luminescence imaging
– Specialized Capabilities : trace elements analysis in olivine. New analytical protocols allow us to measure concentrations of trace elements in olivine down to 20 ppm level. The analytical conditions : Acc. V 25 kV, beam current 900 nA. Since major elements cannot be analysed on WDS at high probe current because of extremely high counting rates and oversaturation of counters, we run Si, Mg, and Fe on ED spectrometer. Precision 2σ obtained by repeated measurement of olivine standards are for major element equivalent of Fo 150 ppm and for trace elements bellow 10 ppm. Total time of analysis - 12 minutes.
– Typical standard errors and detection limits for the new olivine protocol
The combination of modern Jeol JXA-8230 electron probe microanalyser equipped with 5 wavelenght dispersive X-ray spectrometers (WDS) and an energy dispersive SDD X-ray spectrometer (EDS) with highly efficient climate conditioning delivers precision down to 5 ppm 2σ of electron probe microanalysis of olivine.
– Three standard blocks are permanently in the instrument. They contain natural and synthetic silicates, oxides, sulphides, glasses, pure metals and other materials.
– Block 1 and 2 contains commercial standards (P&H Developments Ltd., Calibration Standards for Electron Probe Microanalysis).
– Block 3 contains significant number of Smithsonian Microbeam Standards (Jarosewich, et al 1980) and synthetic glasses provided by Nicole Métrich (IPGP).
– There are additional mounts which contains synthetic REE fluorides and pure metals (REEM25-15) made by Astimex scientific limited ; home-made secondary standards of olivine (XEN) characterised for minor elements by ICP-MS LA in MPI Mainz ; Cr-spinel samples Bar 8601-10 and Dar 8502-2 whose Fe3+/Fetotal ratio had been measured by Mössbauer spectroscopy (Ionov & Wood, 1992).
Samples, thin section or mounts, should well be polished and fit to the holders. In ideal case, the surface should be “mirror smooth” to minimize errors in the matrix correction. The samples must also be stable in a high vacuum environment. The samples must not contain residual oil, uncured epoxy, etc. that will outgas and contaminate the microprobe. Samples must be either electrically conductive or made so by coating with carbon (using our high-vacuum carbon evaporator).
Our sample preparation equipment includes :
– Two grinder-polishers Mataserv 250 – Buehler for preparation polished mounts.
– Cast N’ Vac Castable Vacuum System. The Cast N’ Vac removes trapped air from mounting material.
– Q150TE turbo-pumped a high vacuum carbon coater (Quorum technologies).
The surface of the sample must be electrically conductive to avoid charging by the electron beam. Therefore, insulating samples are carbon coated in vacuum by passing electric current through high purity graphite rods (electrodes). Carbon evaporates at the point of contact of the two electrodes and deposits on the surface of the sample.
CONTACT INFORMATION, SCHEDULING AND FEES
– EPMA Team includes :
Prof. Alexander Sobolev (Scientific director) ; +33(0)4.76.51.41.08
Dr. Valentina Batanova (Lab Manager, operator)
and Valérie Magnin (operator)
– To schedule time on the instrument contact Dr. Valentina Batanova :
valentina.batanova @ univ-grenoble-alpes.fr ; Tel : +33(0)4.76.63.52.23 ; +33(0)4.76.51.40.65
– Daily Rate (24 hours)* :
300 € for indoors users (ISTerre, OSUG).
400 € per day for outdoors users.
For commercial users and specific demands : request for an estimate