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- Author or Editor: J. Tousset x
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Abstract
Ion-beam surface analysis of light elements such as oxygen and carbon in light matrices (boron in our case) is mainly subject to matrix interferences. Using a telescope detection system we show that (d, p) reaction for carbon and proton backscattering for oxygen are able to lead to concentration profiles on the first microns of bulk boron samples. Data processing is described and analytical results are shown, making evidence of the purification obtained using electronic bombardment furnace. Comparing with other phhsical methods of analysis, limitation and improvements of this procedure are discussed.
Abstract
The determination of oxygen in lead and in lead antimony by means of α-activation analysis is described. The separation of fluorine resulting from irradiation of oxygen is performed by extraction with diphenyldichlorosilan in isopropyl ether. In the case of lead antimony alloy, a more complex separation scheme of fluorine from iodine resulting from irradiation of antimony is described.
Abstract
The determination of oxygen in molybdenum by means of α activation analysis is described. The separation of fluorine is performed by extraction with diphenyldichlorosilan. The results concerning oxygen surface concentrations, determined using nuclear reactions induced by low energy deuterons are reminded.
Abstract
Abstract
A non-destructive method is proposed for the determination of fluorine in dental enamel. The detection of the prompt gamma-rays emitted by bombarding with 3 MeV protons lead to the solution of an equation system giving the average fluorine content in the successive layers of the sample. The mathematical treatment of this system is discussed as well as its improvement and generalization.
Abstract
Alpha particles backscattering has been used in order to study the thermal diffusion of gold electrodes into thin films of chalcogenide glasses. The performances of the method allowing approximately a 2000 Å analyzing depth (below the front electrode or near the surface when only back electrode is concerned) diffusion profiles are obtained. If the gold diffusion into As can be considered as classical, following the Fick's law and showing a rather low activation energy (0.6 eV), the diffusion into AsTe is quite different. A flat and deep gold profile develops through the entire thickness of the film (still below the glass transition temperature). A tentative interpretation is proposed, based upon a “preferential path” diffusion, introducing a new diffusion coefficient aside the bulk one. Several significant features support this interpretation and suggest further investigations. Nevertheless we have already a good understanding of the electrical degradation of such devices trough, the correlation with the diffusion process.
Résumé
Une méthode d'étude de la composition stoéchiométrique de couches minces (10 à 500 μg/cm2) de verres chalcogénures est développée. L'étude des réactions nucléaire; induites par bombardement de protons de basse énergie (<4 MeV) sur les éléments constitutifs Ge, As, Te et S, conduit à choisir la diffusion élastique et la détection de gammas prompts pour le dosage simulatené. La précision et la sensibilité de la méthode sont discutées à partir des résultats obtenus. L'utilisation de la résonance fine sur le soufre (p, p'γ) est appliquée à l'étude de l'homogénéité des cibles.
Abstract
A rapid and quantitative separation method of18F in aluminium target, using solvent extraction is presented. Conditions required for aluminium complexation and solvent extraction by means of triphenylantimony dichloride are discussed allowing18F to be finally obtained totally free from all other radiocontaminants.
Abstract
A review is presented summarizing the specific nuclear microanalysis methods applied in our laboratory to study amorphous semiconductor thin films. For backscattering, ∼3 MeV Li ions are applicable when depth resolution and sensitivity are required while up to 8 MeV α-particles allow larger depths to be probed and elemental interferences to be solved. These features are predominant for diffusion studies between metal electrodes and chalcogenide films. On the other hand hydrogen profiling using the1H(1 5N, αψ) resonant nuclear reactions is described and analytical problems associated with its use are discussed. Applications to the elaboration conditions of hydrogenated (a)Si is developed.