"Standardless" Quantitative Electron Probe Microanalysis with Energy-Dispersive X-ray Spectrometry: Is It Worth the Risk?

1995 ◽  
Vol 67 (11) ◽  
pp. 1866-1871 ◽  
Author(s):  
Dale E. Newbury ◽  
Carol R. Swyt ◽  
Robert L. Myklebust
Keyword(s):  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Energy Dispersive ◽  
X Ray ◽  
Quantitative Electron Probe Microanalysis

Measurement and parameterization of ϕ(ρz) curves for quantitative electron probe microanalysis

1990 ◽  
Vol 48 (2) ◽  
pp. 190-191
Author(s):  
J. D. Brown
Keyword(s):  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Absorption Coefficients ◽  
Computing Power ◽  
X Ray ◽  
Practical Applications ◽  
Absorption Correction ◽  
Exponential Decrease ◽  
Quantitative Electron Probe Microanalysis ◽  
Z Curve

The goal of correction methods for quantitative electron probe microanalysis is to convert k-ratios for any type of specimen, any x-ray line and all electron beam energies into accurate concentrations. Early attempts to approach this goal were hindered by sparse data on electron interactions with solids, limited knowledge of x-ray parameters such as mass absorption coefficients and limited computing power which made necessary mathematical simplifications in practical applications.In developing the early models for quantitative analysis, the argument was made that the absorption correction was insensitive to the shape of the ϕ(ρz) curve. For that reason, a number of very crude models which ranged from constant x-ray generation as a function of depth(l) to an exponential decrease from the surface(2) were used. In fact, these models worked quite well for the restricted conditions for which they were designed but of course lack accuracy when applied to more general situations. ϕ(ρz) measurements

Celebrating 40 years of energy dispersive X-ray spectrometry in electron probe microanalysis (EPMA)

2008 ◽  
Vol 14 (S2) ◽  
pp. 1152-1153
Author(s):  
K Keil ◽  
R Fitzgerald ◽  
KFJ Heinrich
Keyword(s):  
New Mexico ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Energy Dispersive ◽  
X Ray

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

EPMA of submicron coatings containing ultralight elements

1992 ◽  
Vol 50 (2) ◽  
pp. 1628-1629
Author(s):  
Peter Willich
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Analytical Sensitivity ◽  
X Ray ◽  
Quantitative Electron Probe Microanalysis ◽  
X Ray Absorption ◽  
Primary Electrons ◽  
Critical Excitation

Materials containing ultralight elements (B, C, N, O) in combination with a metal are of considerable interest in thin film technology. Quantitative electron probe microanalysis of the coatings should be independent of the substrate and has to be carried out under the condition that the ultimate depth of x-ray emission (Rx) is within the provided film thickness of 0.2-0.8 μm. Rx, for an element (critical excitation energy Ec) in a specified matrix is controlled by the energy (E0) of the primary electrons. EPMA of high atomic number elements (Ec = 2-7 keV), under the condition of Rx < 1 μm, frequently requires operation at a low overvoltage of E0/Ec < 2. Consequendy, tne x-ray intensities are very low and the analytical sensitivity is drastically reduced. For the ultralight elements the strong effects oft x-ray absorption always lead to a shallow depth of x-ray emission, even at a high overvoltage.

Quantitative Electron Probe Microanalysis of Nonconducting Specimens: Science or Art?

2004 ◽  
Vol 10 (6) ◽  
pp. 733-738 ◽  
Author(s):  
Guillaume F. Bastin ◽  
Hans J.M. Heijligers
Keyword(s):  
Electrical Conductivity ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Light Element ◽  
X Ray ◽  
Surface Charging ◽  
Quantitative Electron Probe Microanalysis ◽  
Quantitative Analyses ◽  
Intensity Ratios ◽  
Effect Of Surface

The influence of a lack of sufficient electrical conductivity on the results of quantitative electron probe microanalysis has been investigated on a number of oxides. The effect of surface charging and the way it alters the emitted X-ray signals has been studied. It is shown that the presence of conducting coatings, such as carbon or copper, will affect the interelement X-ray intensity ratios, whatever the thickness of the coating may be. Although the effects for heavier elements may be acceptable, they cannot be ignored for a light element such as oxygen, where strong variations with coating thickness were observed. Quantitative analyses of oxygen, on uncoated well-conducting oxide specimens, using uncoated well-conducting hematite (Fe2O3) as a standard yielded excellent results in the range between 4 and 40 kV with the φ(ρz) software used. As soon as coated nonconducting specimens were examined, using the same hematite standard, coated under exactly the same conditions, widely scattering and noncoherent results were obtained. These discrepancies can only be attributed to a lack of conductivity.

Evaluation of energy-dispersive x-ray spectra of low-Zelements from electron-probe microanalysis of individual particles

2001 ◽  
Vol 30 (6) ◽  
pp. 419-426 ◽  
Author(s):  
J. Osán ◽  
J. de Hoog ◽  
P. Van Espen ◽  
I. Szalóki ◽  
C.-U. Ro ◽  
...  
Keyword(s):  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Energy Dispersive ◽  
X Ray ◽  
Individual Particles

Using Quantitative Iteration to Correct for Pathological Spectral Interferences

1998 ◽  
Vol 4 (S2) ◽  
pp. 222-223
Author(s):  
John J. Donovan
Keyword(s):  
Transition Metal ◽  
Electron Probe Microanalysis ◽  
Interference Effect ◽  
Electron Probe ◽  
The Self ◽  
Energy Dispersive ◽  
Spectral Interferences ◽  
X Ray ◽  
To Come ◽  
Secondary Fluorescence

A number of problematic analytical situations are known to exist in electron probe microanalysis (EPMA) where characteristic x-ray spectral overlaps are not only severe, but are also of the “self-interfering” or “cascade” variety. The “self-interfering” variety is exemplified by the innocuous Ba Lα ↔ Ti Kα; to the fearsome Pb Lα↔As Kα binaries, while “cascade” interferences are often seen among the transition metal series as in Ti Kβ → V Kα - V Kα Cr Kα or as seen with a secondary fluorescence interference effect as in Ni K ⇒ Fe Kα - Fe Kβ → Co Kα. Unlike simple interferences of the type Mn Kβ → Fe Kα, both of these types of spectral interferences are often quite troublesome for the analyst to correct for, especially for Si(Li) and Ge energy dispersive spectrometers (EDS) where the analytical peaks are often so overlapped as to prevent graphical deconvolution, and even for the higher resolution wavelength dispersive spectrometers (WDS) along with the yet to come bolometric energy dispersive detectors (based on projected resolution), the task can still be formidable.

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