A Review of Empirical Influence Coefficient Methods in X-Ray Spectrometry

1978 ◽  
Vol 22 ◽  
pp. 281-292 ◽  
Author(s):  
Ron Jenkins
Keyword(s):  
Line Intensity ◽  
Fluorescence Analysis ◽  
General Purpose ◽  
Characteristic Line ◽  
Influence Coefficient ◽  
Analyte Concentration ◽  
Linear Calibration ◽  
X Ray ◽  
Analyte Element ◽  
Non Linear

In the X-ray fluorescence analysis of homogeneous specimens, the correlation between the characteristic line intensity of an analyte element and the concentration of that element, is typically non-linear over wide concentration ranges, due to interelement effects between the analyte element and other elements making up the specimen matrix. Although in many cases limiting the analyte concentration range may allow the use of linear calibration curves based on type-standardisation, it is usually more desirable to work with general purpose calibration schemes which are applicable to a variety of matrix types over wide concentration ranges.

X-Ray Tube Parameters and their Effects on Fluorescence Analysis

1963 ◽  
Vol 7 ◽  
pp. 615-622
Author(s):  
H. T. Dryer
Keyword(s):  
Target Material ◽  
Fluorescence Analysis ◽  
Design Parameters ◽  
Characteristic Line ◽  
Detector Efficiency ◽  
Tube Voltage ◽  
X Ray ◽  
Base Materials ◽  
Main Variable ◽  
Design And Manufacture

AbstractMany variables influence the performance of X-ray fluorescence analysis with regard to speed, precision, accuracy, limits of detection and the elements to be determined. Some of these variables, such as path transmittance, fluorescent yield, and detector efficiency, can be considered constant; however, the primary X-ray beam cannot be assumed a constant. The intensity distribution vs. wavelength function of the X-ray tube remains the main variable with which the X-ray spectrochemist must concern himself in providing optimum analytical performance and speed.This distribution is dependent upon target material, window material and thickness, and tube voltage. Though the overall intensity is dependent upon the atomic number of the target material, the wavelengths of the characteristic line spectrum of the target material can provide additional enhancement for elements which absorb such wavelengths readily.Some of these variables in tube design parameters have been studied to provide comparison performance data on the analysis of a variety of base materials for a number of elements of interest. These data and their interpretation are presented to show how improved fluorescence analysis can be achieved by modifications in X-ray tube design and manufacture.

Micro-Analysis by X-Ray Absorption, Fluorescence, Emission and Diffraction Using Ultra-Fine X-Ray Sources

1957 ◽  
Vol 1 ◽  
pp. 329-337 ◽  
Author(s):  
V. E. Cosslett ◽  
P. Duncumb ◽  
J. V. P. Long ◽  
W. G. Nixon
Keyword(s):  
Line Emission ◽  
Fluorescence Emission ◽  
Fluorescence Analysis ◽  
High Sensitivity ◽  
Characteristic Line ◽  
X Rays ◽  
Emission Analysis ◽  
Thin Sections ◽  
X Ray ◽  
Micro Analysis

AbstractFine focus X-ray tubes developed for projection X-ray microscopy can also be used for X-ray micro-analysis. Areas about 10 microns in diameter of thin sections have been analyzed by measuring differences in X-ray transmission, with particular reference to the determination of calcium in biological materials and in minerals. The high intensity of this X-ray point source has permitted micro-fluorescence analysis of similar small areas with high sensitivity and reasonable time. The same electron optical system has been used for micro-emission analysis of rock slices and mineral grains. By scanning the electron beam over the specimen surface and recording either the scattered electrons or the emitted X-rays, a two-dimensional picture can be displayed of the physical features or of the distribution of a particular element respectively. The analysis of a selected, volume of 1 cubic micron in the surface has been obtained by plotting the characteristic line emission spectrum with a crystal spectrometer and proportional counter. The sensitivity is 0. 1% or 10−1 gram. Micro-beam X-ray diffraction has also been used with a stationary X-ray source both for transmission and back reflection with a 10 minute exposure from a 10 micron diameter area.

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.

Application of Computers in Electron Probe and X-Ray Fluorescence Analysis

1971 ◽  
Vol 15 ◽  
pp. 56-69
Author(s):  
Stanley D. Rasberry
Keyword(s):  
Data Storage ◽  
Great Increase ◽  
Measurement Data ◽  
Fluorescence Analysis ◽  
General Purpose ◽  
Specimen Preparation ◽  
List Type ◽  
X Ray ◽  
The Past ◽  
Routine Service

This paper is a review of automation of electron microprobe and x-ray fluorescence instrumentation. Such a review seems timely because of the great increase in the application of computer systems in this field over the past decade. Some of these applications have been conceived to meet true technological needs while in other cases they have “been undertaken to “keep up with the Joneses.” I would like to show not only what automated systems are now feasible but also when and how they should he employed. The “when” and “how” of automation are largely dependent upon the application being considered; in this study, x-ray applications have been divided into the following classes; (1)on-stream process-control,(2)off-line quality assurance,(3)routine service laboratory,(4)general purpose analytical laboratory. Several phases are present in these classes, including: specimen preparation and loading, measurement, data acquisition and transfer, data processing and display, and finally, archival data storage. Various workers have undertaken the automation of all these operations in one or the other of the classes of applications; from a review of their work and by examining details of each operation within the framework of a given application, we can now draw conclusions on the extent of desirable automation.

Relationship between the reciprocal of analyte--line intensity and the reciprocal of weight fraction and its utilization in x-ray fluorescence analysis

1980 ◽  
Vol 9 (4) ◽  
pp. 176-183 ◽  
Author(s):  
Eiichi Asada ◽  
Shoji Matsuda ◽  
Yoshiko Suzuki ◽  
Mitsuo Nakamura ◽  
Toshiyuki Tone
Keyword(s):  
Line Intensity ◽  
Fluorescence Analysis ◽  
Weight Fraction ◽  
X Ray

An Accurate Coefficient Method for X-Ray Fluorescence Analysis

1975 ◽  
Vol 19 ◽  
pp. 85-111 ◽  
Author(s):  
E. Tertian
Keyword(s):  
Fluorescence Emission ◽  
Fluorescence Analysis ◽  
Present Theory ◽  
Spectrometric Analysis ◽  
Parameter Method ◽  
Influence Coefficient ◽  
Fundamental Parameter ◽  
Factors Affecting ◽  
X Ray ◽  
Image Position

Performing highly automated, computerized X-ray spectrometric analysis ‘without standards’ calls for accurate matrix correction programs which can be based, essentially, on either the ‘fundamental parameter’ method or improved influence coefficient procedures. The coefficient scheme discussed in this paper was devised to strictly comply with the theoretical relationships for X-ray fluorescence emission, thus connecting, in a way, both approaches. This result is achieved by accurately making allowance for the two complicating factors affecting fluorescent intensities i.e. : (1) the mobility of coefficients, and (2) the occurrence of fluorescence crossed effects. The corresponding algorithm, for practical use, writeswhere the (aij + bij ci) terms account for the individual influence coefficients and their variation, and ϵi refers to the overall crossed effect. The essential problem of calibration is then considered, with special emphasis being laid on : (a) experimental coefficient determination, and (b) experimental crossed effect evaluation. Current coefficient methods are briefly surveyed in relation to the present theory.Finally, the advantages of an experimental, accurate coefficient procedure over the fundamental parameter approach, from a practical standpoint, are emphasized.

Modelling Intensity and Concentration in Energy Dispersive X-Ray Fluorescence

1978 ◽  
Vol 22 ◽  
pp. 385-393
Author(s):  
R.B. Shen ◽  
J.C. Russ ◽  
W. Stroeve
Keyword(s):  
Fluorescence Analysis ◽  
Energy Dispersive ◽  
X Rays ◽  
Linear Calibration ◽  
X Ray ◽  
Quantitative Models ◽  
Calibration Curves

It might seem at first glance that quantitative models relating intensity to concentration should be identical for energy - or wavelength - dispersive fluorescence analysis. In both cases the interelement effects that complicate the use of simple linear calibration curves occur in the specimen, at which time the X-rays are not yet aware of which kind of detector will be used to count them. This can be true in some cases, but not in general.

X-Ray Fluorescence Analysis of Niobate-Tantalate Ore Concentrates

1963 ◽  
Vol 7 ◽  
pp. 598-603
Author(s):  
Harry J. Rose ◽  
Robena Brown
Keyword(s):  
Fluorescence Analysis ◽  
Dual Role ◽  
Fluorescence Method ◽  
Linear Calibration ◽  
X Ray ◽  
Fluorescence Measurements ◽  
Refractory Oxides ◽  
Wide Range ◽  
Speed And Accuracy ◽  
Made In

AbstractAn X-ray fluorescence method is described for the analysis of niobotamalate concentrates, bringing speed and accuracy to determinations that are difficult chemically. Many of the problems inherent in the X-ray fluorescence analysis of powdered samples are eliminated by fusion of the sample in a mixture of Li2B4O7 and La2O3. Absolute amounts can be determined without reliance on chemically analyzed standard concentrates. Standards in a wide range of concentrations are readily prepared from pure chemicals. La2O3 plays a dual role, aiding in the fusion of highly refractory oxides and minimizing absorption differences between samples. In addition to niobium and tantalum, elements commonly present in niobate-tantalate ore concentrates, such as titanium, iron, tin, and manganese, are readily determined.The fusion mixture consists of 80 mg of sample, 120 mg of La2O3 and 800 mg of Li2B4O7. The fusion is made in graphite crucibles at 1100°C for 15 min. The cooled bead is ground in a mixer-grinder and pressed into a pellet. X-ray fluorescence measurements yield linear calibration curves for each of the elements over a wide range of concentration.

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