SOME FEATURES OF QUANTITATIVE ANALYSIS OF ROCK-FORMING MINERALS USING A JXA-8230 ELECTRON PROBE MICROANALYZER
Yu.G. Lavrent'ev, L.V. Usova
V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia
Keywords: X-ray electron probe microanalysis, correction methods, metrological characteristics, rock-forming minerals
Abstract
The basic software package of a JXA-8230 microanalyzer, like its predecessor JXA-8100, uses the long-established ZAF correction method (with some differences) for a quantitative analysis: Calculation of mass absorption coefficients is based on Chantler’s theoretical data. The core of this method is quantum-mechanical calculation of the cross section of the interaction between an X-ray photon and atomic electrons. This innovation has had a positive influence on the trueness of X-ray microanalysis. Control tests on specimens where the absorption effect is dominant have demonstrated that the results of this analysis are slightly lower (by less than 2%) independently of the matrix absorption interval in which the analytical line is located. As a consequence, the selection of comparison specimens becomes easier: It is sufficient that the specimen under study and the comparison specimen belong to the same isomorphic series and that the intensity of the analytical line of the comparison specimen allows for the measurement with the required accuracy.
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