Quantitative analysis by X-ray fluorescence using first principles for matrix correction

1978 ◽  
Vol 43 (2) ◽  
pp. 541-557 ◽  
Author(s):  
L. D. Hulett ◽  
H. W. Dunn ◽  
J. G. Tarter
Keyword(s):  
Quantitative Analysis ◽  
First Principles ◽  
Matrix Correction ◽  
X Ray

A Survey of Mathematical Correction Procedures in X-Ray Spectrometry

1975 ◽  
Vol 19 ◽  
pp. 1-17 ◽  
Author(s):  
Ronald Jenkins
Keyword(s):  
First Principles ◽  
Quantitative Data ◽  
Internal Standard ◽  
Characteristic Line ◽  
X Rays ◽  
Matrix Correction ◽  
Internal Standards ◽  
X Ray ◽  
Correction Equations ◽  
Secondary Fluorescence

X-ray spectrometry is an old technique dating back some sixty-odd years and although most of the early interest revolved around the qualitative aspects of the method it wasn't long before attempts were made to obtain quantitative data. One of the first recorded attempts was that by Coster and von Hevesey who in 1923 accurately determined the amount of hafnium in zirconium using tantalum as an internal standard. Glocker and Schreiber were the first to attempt calculation of X-ray characteristic line intensity from first principles although no attempt was made at that time to correct for secondary fluorescence. In von Hevesey's book, “Chemical Analysis by X-Rays,” published in 1932 , a whole chapter is devoted to what is called “Disturbing effects and their avoidance.” Among the effects discussed were primary and secondary absorbtion and third element effects. Matrix correction equations were developed although most of the quantitative work at that time was done using internal standards.

Quantification of Silica Uptake by Alveolar Macrophages - An Emperical Scanning Electron Microprobe Method

1982 ◽  
Vol 40 ◽  
pp. 332-333
Author(s):  
V. V. Damiano ◽  
R. P. Daniele ◽  
H. T. Tucker ◽  
J. H. Dauber
Keyword(s):  
Quantitative Analysis ◽  
Alveolar Macrophages ◽  
Bulk Sample ◽  
Silica Particles ◽  
Empirical Method ◽  
Phagocytic Cells ◽  
Calibration Standards ◽  
X Ray ◽  
Accurate Quantitative Analysis ◽  
Scanning Electron

An important example of intracellular particles is encountered in silicosis where alveolar macrophages ingest inspired silica particles. The quantitation of the silica uptake by these cells may be a potentially useful method for monitoring silica exposure. Accurate quantitative analysis of ingested silica by phagocytic cells is difficult because the particles are frequently small, irregularly shaped and cannot be visualized within the cells. Semiquantitative methods which make use of particles of known size, shape and composition as calibration standards may be the most direct and simplest approach to undertake. The present paper describes an empirical method in which glass microspheres were used as a model to show how the ratio of the silicon Kα peak X-ray intensity from the microspheres to that of a bulk sample of the same composition correlated to the mass of the microsphere contained within the cell. Irregular shaped silica particles were also analyzed and a calibration curve was generated from these data.

Lateral resolution of the electron microbeam analysis

1978 ◽  
Vol 36 (1) ◽  
pp. 542-543
Author(s):  
H.J. Dudek
Keyword(s):  
Quantitative Analysis ◽  
Depth Resolution ◽  
Lateral Resolution ◽  
Cylindrical Particle ◽  
Correction Procedure ◽  
X Ray ◽  
Element Concentrations ◽  
Microbeam Analysis ◽  
The Matrix

The chemical inhomogenities in modern materials such as fibers, phases and inclusions, often have diameters in the region of one micrometer. Using electron microbeam analysis for the determination of the element concentrations one has to know the smallest possible diameter of such regions for a given accuracy of the quantitative analysis.In th is paper the correction procedure for the quantitative electron microbeam analysis is extended to a spacial problem to determine the smallest possible measurements of a cylindrical particle P of high D (depth resolution) and diameter L (lateral resolution) embeded in a matrix M and which has to be analysed quantitative with the accuracy q. The mathematical accounts lead to the following form of the characteristic x-ray intens ity of the element i of a particle P embeded in the matrix M in relation to the intensity of a standard S

Quantitative Analysis Of X-Ray Images From Geological Materials

1990 ◽  
Vol 48 (2) ◽  
pp. 244-245
Author(s):  
J. M. Paque ◽  
R. Browning ◽  
P. L. King ◽  
P. Pianetta
Keyword(s):  
Quantitative Analysis ◽  
Bulk Composition ◽  
Principal Component ◽  
Analytical Description ◽  
Bulk Sample ◽  
Geological Samples ◽  
X Ray ◽  
Software And Hardware ◽  
And Storage ◽  
Insight Into

Geological samples typically contain many minerals (phases) with multiple element compositions. A complete analytical description should give the number of phases present, the volume occupied by each phase in the bulk sample, the average and range of composition of each phase, and the bulk composition of the sample. A practical approach to providing such a complete description is from quantitative analysis of multi-elemental x-ray images.With the advances in recent years in the speed and storage capabilities of laboratory computers, large quantities of data can be efficiently manipulated. Commercial software and hardware presently available allow simultaneous collection of multiple x-ray images from a sample (up to 16 for the Kevex Delta system). Thus, high resolution x-ray images of the majority of the detectable elements in a sample can be collected. The use of statistical techniques, including principal component analysis (PCA), can provide insight into mineral phase composition and the distribution of minerals within a sample.

Computer programs for the calculation of x-ray intensities emitted by elements in multi-layer structures

1990 ◽  
Vol 48 (2) ◽  
pp. 216-217
Author(s):  
G.F. Bastin ◽  
H.J.M. Heijligers ◽  
J.M. Dijkstra
Keyword(s):  
Software Package ◽  
Light Element ◽  
Matrix Correction ◽  
Excellent Performance ◽  
Element Analysis ◽  
X Ray ◽  
Know How ◽  
Accurate Knowledge ◽  
Layer Structures ◽  
Bulk Matrix

For the calculation of X-ray intensities emitted by elements present in multi-layer systems it is vital to have an accurate knowledge of the x-ray ionization vs. mass-depth (ϕ(ρz)) curves as a function of accelerating voltage and atomic number of films and substrate. Once this knowledge is available the way is open to the analysis of thin films in which both the thicknesses as well as the compositions can usually be determined simultaneously.Our bulk matrix correction “PROZA” with its proven excellent performance for a wide variety of applications (e.g., ultra-light element analysis, extremes in accelerating voltage) has been used as the basis for the development of the software package discussed here. The PROZA program is based on our own modifications of the surface-centred Gaussian ϕ(ρz) model, originally introduced by Packwood and Brown. For its extension towards thin film applications it is required to know how the 4 Gaussian parameters α, β, γ and ϕ(o) for each element in each of the films are affected by the film thickness and the presence of other layers and the substrate.

Low-voltage EDS of magnesium ferrite Dendrites in a FEG-SEM

1996 ◽  
Vol 54 ◽  
pp. 478-479
Author(s):  
Matthew T. Johnson ◽  
Ian M. Anderson ◽  
Jim Bentley ◽  
C. Barry Carter
Keyword(s):  
Monte Carlo ◽  
Quantitative Analysis ◽  
Monte Carlo Simulations ◽  
Cross Section ◽  
Spatial Resolution ◽  
Low Voltage ◽  
Magnesium Ferrite ◽  
X Ray ◽  
Interaction Volume ◽  
Ferrite Spinel

Energy-dispersive X-ray spectrometry (EDS) performed at low (≤ 5 kV) accelerating voltages in the SEM has the potential for providing quantitative microanalytical information with a spatial resolution of ∼100 nm. In the present work, EDS analyses were performed on magnesium ferrite spinel [(MgxFe1−x)Fe2O4] dendrites embedded in a MgO matrix, as shown in Fig. 1. spatial resolution of X-ray microanalysis at conventional accelerating voltages is insufficient for the quantitative analysis of these dendrites, which have widths of the order of a few hundred nanometers, without deconvolution of contributions from the MgO matrix. However, Monte Carlo simulations indicate that the interaction volume for MgFe2O4 is ∼150 nm at 3 kV accelerating voltage and therefore sufficient to analyze the dendrites without matrix contributions.Single-crystal {001}-oriented MgO was reacted with hematite (Fe2O3) powder for 6 h at 1450°C in air and furnace cooled. The specimen was then cleaved to expose a clean cross-section suitable for microanalysis.

Comparison of high-angle take-off and low-angle take-off EDX detector geometry of the HF-2000 FE-TEM

1993 ◽  
Vol 51 ◽  
pp. 252-253
Author(s):  
Y. Sato ◽  
T. Hashimoto ◽  
M. Ichihashi ◽  
Y. Ueki ◽  
K. Hirose ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Field Emission ◽  
Solid Angle ◽  
Energy Dispersive ◽  
Objective Lens ◽  
X Rays ◽  
High Angle ◽  
X Ray ◽  
Detector Geometry

Analytical TEMs have two variations in x-ray detector geometry, high and low angle take off. The high take off angle is advantageous for accuracy of quantitative analysis, because the x rays are less absorbed when they go through the sample. The low take off angle geometry enables better sensitivity because of larger detector solid angle.Hitachi HF-2000 cold field emission TEM has two versions; high angle take off and low angle take off. The former allows an energy dispersive x-ray detector above the objective lens. The latter allows the detector beside the objective lens. The x-ray take off angle is 68° for the high take off angle with the specimen held at right angles to the beam, and 22° for the low angle take off. The solid angle is 0.037 sr for the high angle take off, and 0.12 sr for the low angle take off, using a 30 mm2 detector.

Electronic Structure and X-ray Absorption Spectra of Rutile TiO2 Using First-Principles Calculations

2014 ◽  
Vol 52 (12) ◽  
pp. 1025-1029
Author(s):  
Min-Wook Oh ◽  
Tae-Gu Kang ◽  
Byungki Ryu ◽  
Ji Eun Lee ◽  
Sung-Jae Joo ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Absorption Spectra ◽  
First Principles ◽  
First Principles Calculations ◽  
Rutile Tio2 ◽  
X Ray ◽  
X Ray Absorption

Real-Space X-Ray Pair Distribution Function Analysis and Molecular-Dynamics Modelling of Diflunisal Channel Hydrates

2020 ◽  
Author(s):  
Anuradha Pallipurath ◽  
Francesco Civati ◽  
Jonathan Skelton ◽  
Dean Keeble ◽  
Clare Crowley ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Distribution Function ◽  
Structural Dynamics ◽  
First Principles ◽  
Pair Distribution Function ◽  
Function Analysis ◽  
Real Space ◽  
X Ray ◽  
Dynamics Modelling ◽  
Dynamics Simulations

X-ray pair distribution function analysis is used with first-principles molecular dynamics simulations to study the co-operative H<sub>2</sub>O binding, structural dynamics and host-guest interactions in the channel hydrate of diflunisal.

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