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Practical Estimation of Analytical Sensitivity for EDS in an Intermediate Voltage FEG-STEM

Published online by Cambridge University Press:  02 July 2020

M. Watanabe ,
D. W. Ackland  and
D. B. Williams
M. Watanabe
Affiliation:
Department of Materials Science and Engineering, Lehigh University, Bethlehem, PA18015USA
D. W. Ackland
Affiliation:
Department of Materials Science and Engineering, Lehigh University, Bethlehem, PA18015USA
D. B. Williams
Affiliation:
Department of Materials Science and Engineering, Lehigh University, Bethlehem, PA18015USA
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Extract

One of the ultimate objectives for energy-dispersive X-ray spectrometry (EDS) in the analytical electron microscope (AEM) is single-atom detection in thin specimens, as well as quantitative microanalysis with high accuracy approaching ±1% relative. In order to realize the single-atom analysis, the design of the AEM has to be optimized with respect to improvements in spatial resolution and detectability limits. The detectability limit, as defined by the minimum mass fraction (MMF), is given by:

where P is the peak intensity of interest, (P/B) is the peak-to-background ratio for that peak, and r is the acquisition time. To improve the sensitivity for analysis, any or all of the variables P, (P/B), and τ should be increased. Intermediate-voltage analytical electron microscopes combined with high brightness field-emission gun (FEG) are expected to improve the MMF, while maintaining high spatial resolution. Additionally, the MMF should also be improved by maximizing the solid angle of X-ray collection.

Type
Analytical Electron Microscopy
Information
Microscopy and Microanalysis , Volume 3 , Issue S2: Proceedings: Microscopy & Microanalysis '97, Microscopy Society of America 55th Annual Meeting, Microbeam Analysis Society 31st Annual Meeting, Histochemical Society 48th Annual Meeting, Cleveland, Ohio, August 10-14, 1997 , August 1997 , pp. 965 - 966
Copyright
Copyright © Microscopy Society of America 1997

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