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Advances in micro-crystalline inclusion multi-elementary analysis (12<Z<92) by coupled absolute PIXE and RBS

Claire C. Ramboz 1David Strivay 1,5Thierry Sauvage 2Olivier Rouer 1Jean-Paul Gallien 4Hassane Erramli 3

1. Institut des Sciences de la terre d'Orléans (ISTO), 1A, rue de la férollerie, Orléans 45071, France
2. CERI, 3A rue de la Férollerie, Orléans 45071, France
3. Faculty of Sciences Semlalia, Marrakech 4000, Morocco
4. LPS CEA, Gif-sur-Yvette 91191, France
5. University of Liege (ULg), B5, Liège 4000, Belgium

Abstract

Multi-elementary major to trace element analysis of light matrices by PIXE requires the use of a ‘funny filter’ (a filter with a hole drilled at its center placed in front of the detector window) to attenuate the X-Ray emission of the major elements. Previous work by Gama et al. (2001) showed that, assuming the main setup parameters were well constrained (charge, detector physics …), the application of computer-aided PIXE as a multi-elementary absolute analytical method required precise knowledge of the detection geometry parameters (detection solid angle, thickness of the filters and diameter of the hole in the filters). We have developed a simplified procedure that allows multi-elementary PIXE to be applied in an absolute fashion. It relies on the definition of an energy-dependant standardization function G(E) = T(E)*W ( T: filter transmission; W : detection solid angle, E : characteristic X-ray energy of element Z).

Let us consider the p geometrical detection parameters of a PIXE setup and a solid chemical standard the PIXE spectrum of which yields the peaks of N detectable certified elements (N>>p). The computer-assisted PIXE spectrum treatment yields N values of G(E), from which the p detection parameters can be adjusted by a least-square fit procedure. The method is illustrated using a natural basalt standard provided by the SARM laboratory (Nancy, France).17 certified elements from Al to Ba are detected on its PIXE spectrum using an Al-Be ‘funny filter’. The 4 geometrical detection parameters are adjusted to within ± 2 to 6 % on the standard spectrum using the Levenberg-Marquardt algorithm.

We show that, by combining RBS and PIXE measurements, quantitative PIXE can be applied to intracrystalline inclusions placed within the range of protons, as RBS spectrometry provides the geometrical information needed for quantitative elemental analysis of occluded phases.

 

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Presentation: Poster at E-MRS Fall Meeting 2007, Symposium H, by Claire C. Ramboz
See On-line Journal of E-MRS Fall Meeting 2007

Submitted: 2007-06-15 14:07
Revised:   2009-06-07 00:44