Backscatter/Fundamental-Parameters Analysis of Unweighed Samples using Multi-Target, Multi-Crystal Regions of Interest from WDXRF and EDXRF

1991 ◽  
Vol 35 (B) ◽  
pp. 1101-1106
Author(s):  
Richard J. Arthur ◽  
Ronald W. Sanders
Keyword(s):  
Matrix Effects ◽  
Computer Code ◽  
Total Sample ◽  
Regions Of Interest ◽  
Energy Dispersive ◽  
Fundamental Parameter ◽  
Accurate Analysis ◽  
X Ray ◽  
Fundamental Parameters ◽  
Target Energy

AbstractA method has been developed to simultaneously compute matrix corrections from a composite spectrum of multi-target energy-dispersive (EDXRF) and multicrystal wavelength—dispersive (WDXRF) x-ray fluorescence systems, A serial line installed between the WDXRF and EDXRF spectrometers via a PDF 11/34a computer allows acquired wavelength data to be digitally transformed into an energy spectrum. The low-energy x-ray information from the WDXRF unit is then coupled with the backscatter coherent/incoherent information from the EDXRF unit, enabling enhanced quantitative analysis for low-atomic-number (low-Z) elements. The peak resolution obtainable from the WDXRF spectra often removes the necessity for peak-overlap corrections.Backscatter intensities obtained from the EDXRF unit are used to provide information on total sample mass and to correct for matrix effects. The resulting backscatter fundamental-parameter (BFP) calculations generally provide an accurate analysis of samples without prior knowledge of the sample matrix. Such an approach is particularly useful for samples in which quantities of carbon, oxygen, and other low-Z constituents cannot be explicitly determined.Regions of interest (ROI) are created by the computer code “PREP” and processed by the BFP code "MSAP" an extension of the “SAP3” computer program for quantitative multielement analysis by energy-dispersive x-ray fluorescence,

Modified NRLXRF Program for Energy Dispersive X-Ray Fluorescence Analysis

1979 ◽  
Vol 23 ◽  
pp. 99-110
Author(s):  
R.B. Shen ◽  
J. Criss ◽  
J.C. Russ ◽  
A.O. Sandborg
Keyword(s):  
Physical Theory ◽  
Fluorescence Analysis ◽  
Floppy Disk ◽  
Energy Dispersive ◽  
Influence Coefficient ◽  
Fundamental Parameter ◽  
Disk System ◽  
Accurate Analysis ◽  
X Ray ◽  
The Matrix

An X-ray fluorescence program, similar to NRLXRF2 has been written by John Criss to fit into the DEC LSI-11 32K computer with floppy disk system. EDAX has combined the new version with our own software to create a set of FORTRAN programs, called “XRAY 95” to use with the new EDAX EXAM 9500 energy dispersive X-ray fluorescence system. The XRAY 95 program employs both fundamental-parameter equations and influence coefficient equations to optimize the matrix corrections for multicomponent samples. It is an extremely versatile program, using whatever reference standards the user provides and supplementing them with physical theory. The result is a practical approach to fast, accurate analysis.

Characterizing fundamental parameter-based analysis for soil–ceramic matrices in polarized energy-dispersive X-ray fluorescence (PEDXRF) spectrometry

2014 ◽  
Vol 29 (2) ◽  
pp. 159-169 ◽  
Author(s):  
Waleed Amin Abuhani ◽  
Nabanita Dasgupta-Schubert ◽  
Luis Manuel Villaseñor Cendejas
Keyword(s):  
Energy Dispersive ◽  
Standard Reference Materials ◽  
Fundamental Parameter ◽  
X Ray ◽  
Fundamental Parameters ◽  
Matrix Interferences ◽  
Aspect Ratios ◽  
Matrix Properties ◽  
The Matrix ◽  
Powder Samples

Analytical polarized energy-dispersive X-ray fluorescence (PEDXRF) spectrometry (PEDXRFS) represents a substantial advancement over conventional XRF. The higher signal-to-noise commensurate with background lowering and better energy resolution, permits trace analysis for elements with Z ≥ 11. Concomitantly, improvements in analytical software based on the fundamental parameters (FP) approach have improved accuracies and precisions for standard-less analysis (SLA). Two ceramic and soil standard reference materials (SRMs), 98a-Plastic Clay and GSS-1 powders, differed in their intrinsic matrix properties of grain size, bulk, and surface monolayer densities as well as the elemental concentrations. The SRMs were analyzed as powder and as pellets compacted under the same pressure conditions to double the bulk density. Different geometries represented by the sample cup (10, 15, and 24 mm) and pellet (10, 15, and 25 mm) diameters with the same sample thickness (with differing masses and aspect ratios), as well as (for powder samples only) identical low masses (0.5 g) but with varying thicknesses, were analyzed. PEDXRFS combined with TURBOQUANT® (TQ) as SLA-FP enables good quantitative analysis for powders (Z ≥ 13) even for masses significantly lower than recommended, for soil–ceramic samples. Pellets (Z ≥ 12) yielded the best accuracy factor (AF) at high aspect ratio and thicknesses of the matrix analytical depth. Binder in pellets depreciates the AF. TQ needs to adequately quantitate matrix interferences effects, to improve accuracy in the analysis of low atomic numbers, e.g. Na and Mg.

Energy Dispersive XRF Analysis of Lubricating Oil Additives with Secondary Target Excitation and the EXACT Fundamental Parameters Program

1981 ◽  
Vol 25 ◽  
pp. 173-176
Author(s):  
Kenneth C. Stehr
Keyword(s):  
Quality Control ◽  
Petroleum Industry ◽  
Energy Dispersive ◽  
Lubricating Oil ◽  
Accurate Analysis ◽  
X Ray ◽  
Fundamental Parameters ◽  
Unknown Sample ◽  
Oil Additives ◽  
Lubricating Oil Additives

The need for rapid and accurate analysis of lubricating oil additives is firmly established by the petroleum industry. The application of energy dispersive X-ray fluorescence spectrometry techniques to this analysis is a valuable aid in achieving reliable and fast quality control of these product types.Due to the large concentration variations possible for the elements of interest within these materials (principally Zn, Ca, P, S at 0-20%), interelement effects can become significant. In order to correct for interelement effects, historical XRF methods have relied on a large number of standards for each element to be determined or matrix matching with standards closely bracketing the unknown sample concentrations.

Analysis of steels by energy dispersive x-ray fluorescence with fundamental parameters

1982 ◽  
Vol 54 (11) ◽  
pp. 1782-1786 ◽  
Author(s):  
Kirk K. Nielson ◽  
Ronald W. Sanders ◽  
John C. Evans
Keyword(s):  
Energy Dispersive ◽  
X Ray ◽  
Fundamental Parameters

Handheld Portable Energy-Dispersive X-Ray Fluorescence Spectrometry (pXRF)

2016 ◽  
pp. 362-381 ◽  
Author(s):  
Elisabeth Holmqvist
Keyword(s):  
Production Systems ◽  
Matrix Effects ◽  
Chemical Characterization ◽  
High Sensitivity ◽  
Limited Range ◽  
Energy Dispersive ◽  
Analytical Sensitivity ◽  
X Ray ◽  
Non Destructive

Handheld portable energy-dispersive X-ray fluorescence (pXRF) spectrometry is used for non-destructive chemical characterization of archaeological ceramics. Portable XRF can provide adequate analytical sensitivity to discriminate geochemically distinct ceramic pastes, and to identify compositional clusters that correlate with data patterns acquired by NAA or other high sensitivity techniques. However, successful non-destructive analysis of unprepared inhomogeneous ceramic samples requires matrix-defined scientific protocols to control matrix effects which reduce the sensitivity and precision of the instrumentation. Quantification of the measured fluorescence intensities into absolute concentration values and detection of light elements is encumbered by the lack of matrix matched calibration and proper vacuum facilities. Nevertheless, semi-quantitative values for a limited range of high Z elements can be generated. Unstandardized results are difficult to validate by others, and decreased analytical resolution of non-destructive surface analysis may disadvantage site-specific sourcing, jeopardize correct group assignments, and lead to under-interpretation of ceramic craft and production systems.

SUPERXAP- A Personal-Computer-Based Program for Energy-Dispersive X-Ray Spectra Analysis

1992 ◽  
Vol 36 ◽  
pp. 17-25
Author(s):  
D.B. Yager ◽  
J.E. Quick
Keyword(s):  
Least Squares ◽  
Matrix Effects ◽  
Energy Dispersive ◽  
Spectra Analysis ◽  
X Ray ◽  
Peak Overlap ◽  
Elemental Abundances ◽  
On Line ◽  
Computer Based ◽  
Counting Statistics

AbstractSUPERXAP (Super X-ray Analysis Program) enables IBM-compatible personal computers to analyze energy-dispersive spectra using least-squares spectral deconvolution. The program corrects for instrument drift, background, peak overlap, and matrix effects. Pull down menus provide 24 subroutines and functions, that allow spectra to be transferred, stored, viewed, manipulated, and analyzed. Spectral peaks can be identified manually or automatically with color-coded K, L or M lines. Working curves are developed using an interactive routine that creates standard files by least-squares fitting of peak intensities to known elemental abundances. Elemental abundances in unknowns may be determined in a variety of ways including on-line analysis of spectra as they are generated by an energy-dispersive detector and by batch analyses of spectra stored on disk. Standard deviation, based on counting statistics, is reported for each element in each analysis. Written in QuickBASIC 4.5 for interface with a KEVEX 7000 radioactive-source x-ray fluorescence analyzer, SUPERXAP could be adapted, with minor modification, to accept and analyze data from other instruments that produce energy-dispersive spectra.

Energy Dispersive Analysis for Adjacent Elements Using Two Single Channel Analyzers

1971 ◽  
Vol 15 ◽  
pp. 197-208
Author(s):  
Hubert K. Chow
Keyword(s):  
Single Channel ◽  
Matrix Effects ◽  
Pulse Height ◽  
Silicon Detector ◽  
Emission Spectra ◽  
Empirical Method ◽  
Energy Dispersive ◽  
Standard Samples ◽  
X Ray ◽  
Adjacent Element

Energy dispersive x-ray analysis has become an extremely useful analytical tool. The technique provides for the direct observation of x-ray emission spectra, eliminating the need for a dispersive crystal. The purpose of this reported investigation was to study the use of the technique with a simple pulse height analyzing system and to develop a routine method for correcting Interferences due to adjacent element spectral overlap and matrix effects.The analyzing system consists of a radioisotope source, a lithium drifted silicon detector, a preamplifier, an amplifier, two single channel analyzers and two digital ratemeters. In order to obtain results suitable for quantative measurement, a two-step empirical method was employed for the correction of peak overlapping and matrix effects. If two peaks in a spectrum overlap at their tails, one can set up a channel width of the analyzer to a region where there are no overlapping pulses. It is then possible to calibrate the ratio of the intensity obtained from this channel to that obtained from the whole peak in its pure state, i.e. without the appearance of a neighbor peak. The actual intensity of the peak in the overlapping spectrum is, therefore, the observed counts multiplied by the ratio. The next step is the correction of matrix effect by means of conventional empirical methods using standard samples. Two types of the samples, Zn-Cu powder mixtures and Ee-Cu in aqueous solutions, were studied to illustrate this method. The usefulness of applying the analyzing system and technique to industrial measurements, either on-line or batch, will also be discussed.

A Comparison of the XRF11 and EXACT Fundamental Parameters Programs when Using Filtered Direct and Secondary Target Excitation in EDXRF

1982 ◽  
Vol 26 ◽  
pp. 369-376 ◽  
Author(s):  
Ronald A. Vane
Keyword(s):  
Energy Dispersive ◽  
Fluorescence Spectrometry ◽  
X Ray ◽  
Fundamental Parameters ◽  
Secondary Target ◽  
Direct Excitation

The XRF11 program by John Criss and the EXACT program are two commercially available fundamental parameters programs for energy dispersive x-ray fluorescence spectrometry (EDXRF). These programs are both based on the same underlying equations but use different approaches to the calculations. The EXACT program assumes monochromatic excitation, and the XEF11 program models polychromatic excitation sources. There are also great differences in how the two programs approach the iterations in the calculations and in how the data from standards are used in the two programs for calibration.To produce the monochromatic excitation neeiled by the EXACT program, secondary targets have been the preferred method. But it is also possible to approximate monochromatic excitation by using filtered direct excitation. The purpose of this study is to compare the data obtained from both secondary targets and direct filtered excitation as processed through both XRF11 and EXACT.

Fundamental-Parameters Calculations on a Laboratory Microcomputer

1979 ◽  
Vol 23 ◽  
pp. 93-97 ◽  
Author(s):  
J. W. Criss
Keyword(s):  
Computer Program ◽  
Full Advantage ◽  
Data Base ◽  
Software Package ◽  
Fluorescence Analysis ◽  
Absorption Coefficients ◽  
Accurate Analysis ◽  
X Ray ◽  
Fundamental Parameters ◽  
Automatic Treatment

Fundamental-parameters calculations can be made on a laboratory microcomputer fo r automatic treatment of interelement absorption and enhancement effects in x-ray fluorescence analysis. A new software package, called XRF-11, uses an efficient combination of fundamental parameters and alpha factors to compensate for any lack of measured reference materials, while taking full advantage of whatever standards are available, even just pure elements. In many cases, one multi-element standard is enough for accurate analysis.The new XRF-11 software uses the same data base of absorption coefficients, fluorescence yields, etc. as the big-computer program NRLXRF, and combines theory with experiment in a consis tent way that is similar to, but more efficient than, the treatment used in NRLXRF.

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