Method for Finding Mass-Absorption Coefficients by Empirical Equations and Graphs

1962 ◽  
pp. 153-160 ◽  
Author(s):  
J. Leroux
Keyword(s):  
Empirical Equations ◽  
Absorption Coefficients ◽  
Mass Absorption

Method for Finding Mass-Absorption Coefficients by Empirical Equations and Graphs

1961 ◽  
Vol 5 ◽  
pp. 153-160 ◽  
Author(s):  
J. Leroux
Keyword(s):  
Experimental Data ◽  
Empirical Equation ◽  
The Other ◽  
Empirical Equations ◽  
Absorption Coefficients ◽  
Modern Equipment ◽  
Mass Absorption ◽  
Complete Set ◽  
Logical Order ◽  
The Relationship

AbstractA brief description of the theoretical approach of this new method is given. The main purpose of the method is to correlate in a more logical order not only the data yielding the two laws relating mass-absorption coefficient to wavelength and to atomic number, respectively, but also to delineate, within two discontinuities, the relationship existing between each value and the other ones taken as a whole. The empirical equation relating μ to λ is μ = Cλn. A table of complete values for the constant C and die power n to be assigned in the equation is given for finding the values of mass-absorption coefficients above unity for all elements (except hydrogen) and for all wavelengths between 0.17837 and 10 A. It is believed that until a complete set of experimental data obtained with modern equipment is available, this proposed method fills the enormous gaps between actual compiled values.

Mass Absorption Coefficient Measurements Using Thin Films

1969 ◽  
Vol 13 ◽  
pp. 632-638 ◽  
Author(s):  
P. Lublin ◽  
P. Cukor ◽  
R. J. Jaworowski
Keyword(s):  
Thin Films ◽  
Absorption Coefficient ◽  
Mass Absorption Coefficient ◽  
Absorption Coefficients ◽  
Electron Probe Analysis ◽  
Mass Absorption ◽  
Probe Analysis ◽  
Absorption Correction ◽  
Thin Foils ◽  
Metal Organic

For quantitative electron probe analysis, the raw intensity ratios must be corrected to take into account deviations due to absorption, fluoresecnce and electron beam penetration. The major correction is usually the absorption correction, so that for best results, accurate mass absorption coefficients are required. Many tables of absorption coefficients are calculated by interpolation or extrapolation from available measured values, and therefore new measurements are required for increased reliability. The region which requires the most attention for present-day probe analysis is the 2 to 10 Å range.Thin foils of the lighter metals are available for mass absorption coefficient measurements, but heavy metal foils, which must be extremely thin, are not obtainable, A method has been developed to prepare thin films of heavy metals on a suitable substrate by pyrolytic decomposition of metal organic compounds.

Measurement of Mass Absorption Coefficients Using Compton-Scattered Cu Radiation in X-ray Diffraction Analysis

1990 ◽  
Vol 34 ◽  
pp. 325-335 ◽  
Author(s):  
Steve J. Chipera ◽  
David L. Bish
Keyword(s):  
Chemical Composition ◽  
Solid State ◽  
Absorption Coefficient ◽  
Mass Absorption Coefficient ◽  
X Rays ◽  
X Ray Diffraction ◽  
Absorption Coefficients ◽  
Solid State Detector ◽  
X Ray ◽  
Mass Absorption

AbstractThe mass absorption coefficient is a useful parameter for quantitative characterization of materials. If the chemical composition of a sample is known, the mass absorption coefficient can be calculated directly. However, the mass absorption coefficient must be determined empirically if the chemical composition is unknown. Traditional methods for determining the mass absorption coefficient involve measuring the transmission of monochromatic X-rays through a sample of known thickness and density. Reynolds (1963,1967), however, proposed a method for determining the mass absorption coefficient by measuring the Compton or inelastic X-ray scattering from a sample using Mo radiation on an X-ray fluorescence spectrometer (XRF). With the recent advances in solid-state detectors/electronics for use with conventional powder diffractometers, it is now possible to readily determine mass absorption coefficients during routine X-ray diffraction (XRD) analyses.Using Cu Kα radiation and Reynolds’ method on a Siemens D-500 diffractometer fitted with a Kevex Si(Li) solid-state detector, we have measured the mass absorption coefficients of a suite of minerals and pure chemical compounds ranging in μ/ρ from graphite to Fe-metal (μ/ρ = 4.6-308 using Cu Kα radiation) to ±4.0% (lσ). The relationship between the known mass absorption coefficient and the inverse count rate is linear with a correlation coefficient of 0.997. Using mass absorption coefficients, phase abundances can be determined during quantitative XRD analysis without requiring the use of an internal standard, even when an amorphous component is present.

Optimizing the Calculation of Standardless Quantitative Analysis

1988 ◽  
Vol 32 ◽  
pp. 515-522
Author(s):  
Lu Jinsheng ◽  
Xie Ronghou ◽  
Tan Xiaoqun ◽  
C. Nieuwenhuizen
Keyword(s):  
Quantitative Analysis ◽  
Phase Analysis ◽  
Quantitative Phase Analysis ◽  
Absorption Coefficients ◽  
Quantitative Phase ◽  
Mass Absorption ◽  
Pure Phases

A method for quantitative phase analysis without standards (QPAWS) has been published in 1977 and has gained considerable interest, as the calibration for quantitative XRD may sometimes be difficult. Standards for quantitatative XRD are not generally available, and in many cases even the pure phases cannot be obtained.The QPAWS method is based on (i) analysis of all phases present in the samples, (ii) foreknowledge of mass absorption coefficients (MAC)(iii) measuring samples which contain all phases in varying concentrations. In this method the number of samples used is equal to the number of phases to be analysed.

scholarly journals Approximating the near-edge mass absorption coefficients for Ni using an ultra-thin bimetal foil

2017 ◽  
Vol 50 (1) ◽  
pp. 1-13 ◽  
Author(s):  
R. W. Alkire
Keyword(s):  
Foil Thickness ◽  
Single Element ◽  
Metal Foil ◽  
Edge Region ◽  
Absorption Coefficients ◽  
Beam Position ◽  
Mass Absorption ◽  
Continuous Map ◽  
Fitting Procedure ◽  
Absorption Measurements

In an effort to improve the characteristics of a fluorescing metal-foil-based beam position monitor, a new bimetal ultra-thin (0.98/0.67 µm) Ti–Ni foil was introduced to replace an existing single-element ultra-thin 0.5 µm thick Cr foil. During characterization it was determined that absorption measurements on the bimetal foil could be used to fit the Ni mass absorption coefficients accurately in the vicinity of the Ni K edge. Comparison with experimental results from the literature demonstrated that the fitting procedure produced coefficients with uncertainties of the order of ±1%. Once determined, these fit coefficients allowed the thickness of an independently mounted 8 µm thick Ni foil to be computed from absorption measurements instead of relying on a tool-based measurement of the foil thickness. Using the 8 µm thick foil, a continuous map of Ni mass absorption coefficients was produced at 1 eV resolution throughout the near-edge region. This high-resolution map marks a significant improvement over the existing NIST XCOM or FFAST database mass absorption coefficients, which have estimated errors of 10–20% for the near-edge region.

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