Change in the Chemical Composition of an Analyzed Object During Low-Voltage Electron Probe X-Ray Spectral Microanalysis

AbstractConventional electron-probe microanalysis has an X-ray analytical spatial resolution on the order of 1–4 μm width/depth. Many of the naturally occurring Fe–Si compounds analyzed in this study are smaller than 1 μm in size, requiring the use of lower accelerating potentials and nonstandard X-ray lines for analysis. Problems with the use of low-energy X-ray lines (soft X-rays) of iron for quantitative analyses are discussed and a review is given of the alternative X-ray lines that may be used for iron at or below 5 keV (i.e., accelerating voltage that allows analysis of areas of interest <1 μm). Problems include increased sensitivity to surface effects for soft X-rays, peak shifts (induced by chemical bonding, differential self-absorption, and/or buildup of carbon contamination), uncertainties in the mass attenuation coefficient for X-ray lines near absorption edges, and issues with spectral resolution and count rates from the available Bragg diffractors. In addition to the results from the traditionally used Fe Lα line, alternative approaches, utilizing Fe Lβ, and Fe Ll-η lines, are discussed.

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A new and versatile computer program for correcting EPMA data

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100132923 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1658-1659

Author(s):

I Farthing ◽

G Love ◽

VD Scott ◽

CT Walker

Keyword(s):

Chemical Composition ◽

Computer Program ◽

Programming Language ◽

Atomic Number ◽

Processing Speed ◽

Electron Probe Microanalysis ◽

Electron Probe ◽

Epma Data ◽

X Ray ◽

X Ray Absorption

A new computer program has been developed to convert electron probe microanalysis data into accurate measurements of chemical composition. It is menu-based and designed to operate off-line using any IBM PC compatible computer. As shown in the flowchart, fig. 1, the architecture is modular and the programming language adopted is a compilable version of BASIC which possesses much of the processing speed associated with FORTRAN or C. Specimens containing up to fifteen elements, with 4 ≤ Z ≤ 96, can be handled and all the major x-ray lines (Kα, Kβ, Lα, L(β, Mα and Mβ) are available for analysis purposes.The procedure itself is based upon the classical ZAF approach in which corrections for atomic number (Z), x-ray absorption (A), characteristic fluorescence (Fl) and continuum fluorescence (F2) are treated independently. The factors dealing with fluorescence are essentially those of Reed (characteristic) and Springer (continuum) although both contain minor updates. However, the atomic number and absorption factors are the authors' own and the latter, developed from a quadrilateral representation of the x-ray distribution with depth in a solid, distinguishes this program from others.

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Peculiarities Of The Diatom Valve Chemical Composition (Inorganic Components) Study By Electron Probe X-Ray Microanalysis

METHODS AND OBJECTS OF CHEMICAL ANALYSIS ◽

10.17721/moca.2014.65-72 ◽

2014 ◽

Vol 9 (2) ◽

pp. 65-72

Author(s):

L.A. Pavlova ◽

◽

L.L. Tkachenko ◽

A.V. Goreglyad ◽

M.I. Kuzmin ◽

...

Keyword(s):

Chemical Composition ◽

Electron Probe ◽

X Ray ◽

Inorganic Components ◽

Diatom Valve

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Thermoelectric Properties of InxCo4-yNiySb12 Skutterudite Compounds

MRS Proceedings ◽

10.1557/proc-1044-u05-06 ◽

2007 ◽

Vol 1044 ◽

Cited By ~ 2

Author(s):

Veronique Da Ros ◽

Juliusz Leszczynski ◽

Bertrand Lenoir ◽

Anne Dauscher ◽

Christophe Candolfi ◽

...

Keyword(s):

Thermal Conductivity ◽

Electrical Resistivity ◽

Thermal Properties ◽

Chemical Composition ◽

Thermoelectric Power ◽

Thermoelectric Properties ◽

Electron Probe Microanalysis ◽

Electron Probe ◽

X Ray Diffraction ◽

X Ray

AbstractThe preparation of partially filled n-type InxCo4Sb12 skutterudite compounds has been recently reported. The results were particularly promising, the materials exhibiting a ZT value far higher than one at moderated temperature. In this paper, we propose to investigate another way to tune the electrical and thermal properties by substituting Co atoms by Ni atoms in InxCo4Sb12. InxCo4-yNiySb12 polycrystalline samples have been prepared by a conventional metallurgical route. Structural analyses have been carried out by X-ray diffraction. The chemical composition and micro-homogeneity have been checked by electron probe microanalysis. Measurements of the electrical resistivity, thermoelectric power and thermal conductivity have been performed between 300 and 800 K. The influence of the presence of Ni on the thermoelectric properties of InxCo4Sb12 compounds is presented and discussed.

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Investigation of the chemical composition of (Na1−xBix)(MnyNb1−y)O3 ceramics by single particle electron probe X-ray microanalysis with an application of Monte Carlo simulations

Spectrochimica Acta Part B Atomic Spectroscopy ◽

10.1016/j.sab.2005.03.013 ◽

2005 ◽

Vol 60 (4) ◽

pp. 525-530 ◽

Cited By ~ 7

Author(s):

Z. Spolnik ◽

J. Osán ◽

M. Klepka ◽

K. Lawniczak-Jablonska ◽

R. Van Grieken ◽

...

Keyword(s):

Monte Carlo ◽

Chemical Composition ◽

Monte Carlo Simulations ◽

Single Particle ◽

Electron Probe ◽

X Ray

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Electron microscopic and electron probe x-ray microanalysis (EPXMA) of prostatic intraluminal “crystalloids”

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100123441 ◽

1992 ◽

Vol 50 (1) ◽

pp. 608-609

Author(s):

H.X. Bui ◽

A. delRosario ◽

M. Abdulla ◽

C.E. Sheehan ◽

R.J. Emerson ◽

...

Keyword(s):

Chemical Composition ◽

Light Microscopy ◽

Electron Probe ◽

Prostatic Adenocarcinoma ◽

Electron Microscopic ◽

X Ray ◽

Significant Potential ◽

Well Differentiated ◽

Benign Prostate

Prostatic intraluminal “crystalloids” are intensely eosinophilic, non-birefringent crystalline-like structures readily identified with light microscopy. Well documented to be associated with prostatic adenocarcinoma, these rhomboidal, hexagonal, triangular, polyhedral, or needle-like structures are almost exclusively confined to well differentiated prostatic adenocarcinomas and may occasionally be seen in adjacent benign glands bordering the tumors. Although of significant potential as a signal of nearby cancer in a limited biopsy of benign prostate, these “crystalloids” are poorly defined and their chemical composition has not been determined.

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MgCu4(SO4)2(OH)6 · 6H2O, the magnesium analogue of ktenasite from the Casualidad mine near Baños de Alhamilla, Almeria, Spain

Neues Jahrbuch für Mineralogie - Abhandlungen Journal of Mineralogy and Geochemistry ◽

10.1127/njma/2020/0218 ◽

2020 ◽

Author(s):

Jochen Schlüter ◽

Thomas Malcherek ◽

Boriana Mihailova ◽

Christian Rewitzer ◽

Rupert Hochleitner ◽

...

Keyword(s):

Refractive Index ◽

Chemical Composition ◽

Electron Probe ◽

New Mineral ◽

Environmental Sciences ◽

Unit Cell Parameters ◽

Single Crystal Diffraction ◽

X Ray ◽

Cell Parameters ◽

Perfect Cleavage

The new mineral fehrite (IMA 2018-125a), MgCu4(SO4)2(OH)6 · 6H2O, is a member of the ktenasite group andthe Mg-analogue of ktenasite, ZnCu4(SO4)2(OH)6 · 6H2O. The mineral was found in the Casualidad mine near Baños deAlhamilla, Almeria, Spain, in association with clinoatacamite, kapellasite, gordaite, serpierite, connellite and gypsum.The transparent turquoise-coloured mineral has a vitreous lustre, exhibits a pale blue-green streak and shows distinctpleochroism. It forms radial aggregates of thin lath-like crystals of up to 200 μm in length. Fehrite is not fluorescent. Themonoclinic crystals show a perfect cleavage parallel to {001}. The mineral has a brittle tenacity and an uneven fracture. Thecalculated density is 2.73 g/cm3, the calculated mean refractive index is 1.584. The strongest lines observed in the X-raypowder diffraction pattern are [d in Å/Irel in %/(hkl)] 11.94/100/002, 5.92/31/004, 2.66/12/202, 4.85/11/013, 3.93/11/006and 2.96/10/008. The chemical composition, measured by means of an electron probe micro-analyser, was determined at(wt.%): MgO 5.31, MnO 0.49, CuO 33.12, ZnO 11.48, SO3 26.01, H2Ocalc. 24.63, total 101.04. The empirical formula basedon 20 O pfu., including 6(OH) and 6(H2O), is Mg0.87Cu2.74Zn0.93Mn0.05S2.14O8(OH)6 · 6H2O. The simplified end memberformula is MgCu4(SO4)2(OH)6 · 6H2O which requires MgO 5.92, CuO 46.74, SO3 23.52, H2O 23.82, total 100.00 (wt.%).Fehrite is monoclinic with space group P21/c (#14). Unit cell parameters determined by X-ray single crystal diffraction area = 5.6062(8), b = 6.1294(11), c = 23.834(3) Å, β = 95.29(1)º, V = 815.5(2) Å3, Z = 2. The mineral is isotypic with ktenasitewith Mg in place of Zn. The name is for the late Karl Thomas Fehr (1954 – 2014), Professor of Mineralogy at the Departmentof Geo- and Environmental Sciences at the Ludwig-Maximilians-University Munich, Germany.

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Electron Probe Microanalysis Through Coated Oxidized Surfaces

Microscopy and Microanalysis ◽

10.1017/s1431927619014715 ◽

2019 ◽

Vol 25 (05) ◽

pp. 1112-1129 ◽

Cited By ~ 1

Author(s):

Mike B. Matthews ◽

Ben Buse ◽

Stuart L. Kearns

Keyword(s):

Electron Probe Microanalysis ◽

Electron Probe ◽

Low Voltage ◽

Layer Structure ◽

Oxide Thickness ◽

Linear Functions ◽

Voltage Electron ◽

Before And After ◽

20 Nm ◽

Good Agreement

AbstractLow voltage electron probe microanalysis (EPMA) of metals can be complicated by the presence of a surface oxide. If a conductive coating is applied, analysis becomes one of a three-layer structure. A method is presented which allows for the coating and oxide thicknesses and the substrate intensities to be determined. By restricting the range of coating and oxide thicknesses, tc and to respectively, x-ray intensities can be parameterized using a combination of linear functions of tc and to. tc can be determined from the coating element k-ratio independently of the oxide thickness. to can then be derived from the O k-ratio and tc. From tc and to the intensity components of the k-ratios from the oxide layer and substrate can each be derived. Modeled results are presented for an Ag on Bi2O3 on Bi system, with tc and to each ranging from 5 to 20 nm, for voltages of 5–20 kV. The method is tested against experimental measurements of Ag- or C-coated samples of polished Bi samples which have been allowed to naturally oxidize. Oxide thicknesses determined both before and after coating with Ag or C are consistent. Predicted Bi Mα k-ratios also show good agreement with EPMA-measured values.

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Improving the Analtical Accuracy in the Analysis of Particles by Employing Low Voltage Analysis:

Microscopy and Microanalysis ◽

10.1017/s1431927600037119 ◽

2000 ◽

Vol 6 (S2) ◽

pp. 924-925

Author(s):

JA Small ◽

JT Armstrong

Keyword(s):

Electron Beam ◽

Electron Probe ◽

Low Voltage ◽

X Rays ◽

Relative Uncertainty ◽

Particle Volume ◽

X Ray ◽

Uncertainty Estimates ◽

Corrected Data ◽

Particle Geometry

The energy of the electron beam, in conventional electron probe microanalysis, is generally in the range of 15-25 keV which provides the necessary overvoltage to excite efficiently the K and L x-ray lines for elements with atomic numbers in the range of about 5-83. One of the primary microanalytical methods for obtaining compositional information on particles is X-ray analysis in the electron probe and these same voltage criteria have been applied to the procedures developed for this purpose. The main difference in analytical procedures for bulk samples and particles is that corrections have to be applied to the particle k-ratios or calculated compositions to compensate for: 1) the penetration or scattering of electrons out of the particle volume and 2) variations in the absorption due to particle geometry of x-rays less than about 3 keV. In general, particle corrections improve the accuracy and reduce the relative uncertainty estimates from several tens of percent for uncorrected data to about 10% for corrected data.

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