Values of K-shell partial cross-section for electron energy-loss spectrometry

The measurement of trace level constituents, arbitrarily defined for this study as concentration levels below 1 atom percent, has always been considered problematic for analytical electron microscopy (AEM) with energy dispersive x-ray spectrometry (EDS) and electron energy loss spectrometry (EELS). In a landmark study of various microanalysis techniques, Wittry evaluated the influence of various instrumental factors (source brightness, detection efficiency, accumulation time) and physical factors (cross section, peak-to-background) upon detection limits. Although the ionization cross section, fluorescence yield, and collection efficiency favor EELS over EDS, the peak-to-background ratio of EELS spectra is much lower than that of EDS spectra, leading Wittry to suggest that the limit of detection should be 0.1 percent for EDS and 1 percent for EELS for practical measurement conditions. Recent developments in parallel detection EELS (PEELS) indicate that a re-evaluation of the situation for trace constituent determination is needed for those elements characterized by "white line" resonance structures at the ionization edge.

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Accurate quantification of lithium in aluminium-lithium alloys with electron energy-loss spectrometry

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1989.0100 ◽

1989 ◽

Vol 425 (1868) ◽

pp. 91-111 ◽

Cited By ~ 7

Keyword(s):

Energy Loss ◽

Electron Energy ◽

Partial Cross Section ◽

Specimen Preparation ◽

Transmission Electron ◽

Electron Energy Loss Spectrometry ◽

Δ Phase ◽

Extrapolation Scheme ◽

Electron Energy Loss ◽

Accurate Quantification

The composition of the Al 3 Li (δ)' metastable precipitation-hardening phase is an important factor in understanding the strengthening behaviour of Al-Li base alloys. The procedure for using electron energy-loss spectrometry in a transmission electron microscope for accurate quantification of the Li content of δ' is established. All factors that can affect the accuracy of the analysis procedure are considered, namely: the specimen preparation, the mode of operation of the microscope, the identification of spectra from through-thickness regions of the specimen, the calibration of the Li / Al partial cross-section ratio, the deconvolution of the spectra and the background extrapolation scheme. The composition of the δ' phase in the temperature range 155-290 °C is determined, and the non-stoichiometry of this phase is clearly shown.

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A Poor Man’s Approach to Semi-Quantitative Analysis with Electron Energy Loss Spectroscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s143192760000043x ◽

1980 ◽

Vol 38 ◽

pp. 110-111

Author(s):

M. Isaacson

Keyword(s):

Quantitative Analysis ◽

Energy Loss ◽

Electron Energy ◽

Cross Section ◽

Electron Energy Loss Spectroscopy ◽

Excitation Cross Section ◽

Incident Electron ◽

Integral Cross Section ◽

Image Position ◽

Electron Energy Loss

In an earlier paper1 it was found that to a good approximation, the efficiency of collection of electrons that had lost energy due to an inner shell excitation could be written as where σE was the total excitation cross-section and σE(θ, Δ) was the integral cross-section for scattering within an angle θ and with an energy loss up to an energy Δ from the excitation edge, EE. We then obtained: where , with P being the momentum of the incident electron of velocity v. The parameter r was due to the assumption that d2σ/dEdΩ∞E−r for energy loss E. In reference 1 it was assumed that r was a constant.

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In Situ Analysis of Surface Contaminant Desorption during Low-Temperature Silicon Substrate Cleaning using Reflection Electron Energy Loss Spectrometry

MRS Proceedings ◽

10.1557/proc-259-449 ◽

1992 ◽

Vol 259 ◽

Cited By ~ 1

Author(s):

Selmer S. Wong ◽

Shouleh Nikzad ◽

Channing C. Ahn ◽

Aimee L. Smith ◽

Harry A. Atwater

Keyword(s):

Low Temperature ◽

Energy Loss ◽

Electron Energy ◽

Core Loss ◽

Temperature Dependent ◽

Electron Energy Loss Spectrometry ◽

Analysis Technique ◽

Chemical Analysis Technique ◽

Electron Energy Loss

ABSTRACTWe have employed reflection electron energy loss spectrometry (REELS), a surface chemical analysis technique, in order to analyze contaminant coverages at the submonolayer level during low-temperature in situ cleaning of hydrogen-terminated Si(100). The chemical composition of the surface was analyzed by measurements of the C K, O K and Si L2,3 core loss intensities at various stages of the cleaning. These results were quantified using SiC(100) and SiO2 as reference standards for C and O coverage. Room temperature REELS core loss intensity analysis after sample insertion reveals carbon at fractional monolayer coverage. We have established the REELS detection limit for carbon coverage to be 5±2% of a monolayer. A study of temperature-dependent hydrocarbon desorption from hydrogen-terminated Si(100) reveals the absence of carbon on the surface at temperatures greater than 200°C. This indicates the feasibility of epitaxial growth following an in situ low-temperature cleaning and also indicates the power of REELS as an in situ technique for assessment of surface cleanliness.

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