scholarly journals The absorption of X-rays

1925 ◽  
Vol 107 (742) ◽  
pp. 312-331 ◽  
Keyword(s):  
Direct Method ◽  
Comparison Method ◽  
Balance Method ◽  
X Rays ◽  
Absorption Coefficients ◽  
Mass Absorption ◽  
The Absolute ◽  
Constant Source

An account is given here of the measurement, by a balance method, of the mass-absorption coefficients of a number of elements, primarily relative to aluminium, over a range of wave-lengths from 0·3 to 0·7 Å. U., and of the absolute coefficient of aluminium itself for three wave-lengths. The main objection to the direct method of measuring absorption coefficients is the difficulty, with ordinary facilities, of obtaining an even approximately constant source of X-rays. This necessitates the use of some form of compensation or comparison method.

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.

Low Energy Mass Absorption Coefficients from Proton Induced X-ray Spectroscopy

1976 ◽  
Vol 20 ◽  
pp. 481-486 ◽  
Author(s):  
A. Lurio ◽  
W. Reuter ◽  
J. Keller
Keyword(s):  
Energy Range ◽  
Experimental Technique ◽  
Low Energy ◽  
X Rays ◽  
Proton Bombardment ◽  
Absorption Coefficients ◽  
X Ray ◽  
Mass Absorption

We describe a new and reliable experimental technique for the measurement of mass absorption coefficients in the 0.1 to 1 keV energy range. In this technique, the absorbing film is supported directly on a substrate which under proton bombardment will generate the x-rays whose absorption will be measured. Results are given for thirteen different metals at the C Kα (277 eV) line.

The Impact of Chemical Bonding on Mass Absorption Coefficients of Soft X-rays

2020 ◽  
Vol 26 (4) ◽  
pp. 741-749
Author(s):  
Samantha Rudinsky ◽  
Nicholas C. Wilson ◽  
Colin M. MacRae ◽  
Yu Yuan ◽  
Hendrix Demers ◽  
...  
Keyword(s):  
Chemical Bonding ◽  
X Rays ◽  
Absorption Coefficients ◽  
Mass Absorption ◽  
The Impact

Abstract

Some Measurements on the Absorption of X-Rays of Long Wave-length

1927 ◽  
Vol 23 (7) ◽  
pp. 783-793 ◽  
Author(s):  
L. H. Martin
Keyword(s):  
Wave Length ◽  
X Rays ◽  
Absorption Coefficients ◽  
Mass Absorption ◽  
Long Wave ◽  
Nickel Copper ◽  
Length Range ◽  
Iron Nickel

An account is given here of the measurements of the mass absorption coefficients of iron, nickel, copper and aluminium over a wave-length range 0·705 Å.U. to 1.932 Å.U.

A METHOD OF MEASURING ABSORPTION COEFFICIENTS FOR X-RAYS BY MEANS OF A TRI-ELECTRODE IONIZATION CHAMBER

1936 ◽  
Vol 14a (12) ◽  
pp. 209-215
Author(s):  
G. A. Wrenshall ◽  
E. L. Harrington
Keyword(s):  
Ionization Chamber ◽  
Balance Method ◽  
X Rays ◽  
Complete Elimination ◽  
Absorption Coefficients ◽  
Sources Of Error ◽  
New Form ◽  
Absorbing Media ◽  
Direct Calculations

A balance method of measuring absorption coefficients for X-rays in absorbing media, using a new form of sectored discs for determining alterations in intensity and an ionization chamber containing three electrodes, has been developed. The new arrangement makes possible a simplification of the apparatus, a complete elimination of certain sources of error, and very direct calculations of the results. A curve is included in this report to indicate the accuracy routinely attainable.

scholarly journals Quantification of Olivine Using Fe Lα in Electron Probe Microanalysis (EPMA)

2018 ◽  
Vol 24 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Ben Buse ◽  
Stuart Kearns
Keyword(s):  
Solid Solution ◽  
Transition Probabilities ◽  
Fluorescence Yield ◽  
X Rays ◽  
Solid Solution Series ◽  
Absorption Coefficients ◽  
Mass Absorption ◽  
Systematic Discrepancy ◽  
Measured Mass ◽  
Good Agreement

AbstractQuantification of first series transition metal Lα X-rays is hampered by absorption and in some cases transition probabilities (fluorescence yields) varying with chemical bonding. Compound mass absorption coefficients for Fe Lα were measured in the olivine solid solution series [Forsterite (Mg2SiO4) to Fayalite (Fe2SiO4)] and the mass absorption coefficients for Fe Lα absorbed by Fe were calculated. The mass absorption coefficients vary systematically between Fo83 and Fo0. Using the measured mass absorption coefficients for both standard and unknown and by correcting for a systematic discrepancy, consistent with varying partial fluorescence yields, a good agreement between calculated k-ratios and measured k-ratios is achieved. The systematic variations allow quantification of unknown k-ratios. The described method of quantification requires modification of matrix correction routines to allow standards and unknowns to have different mass absorption coefficients, and to incorporate solid solution mass absorption coefficients and partial fluorescence yield corrections derived from regression of experimental data.

SAXS experiments on absolute scale with Kratky systems using water as a secondary standard

2000 ◽  
Vol 33 (2) ◽  
pp. 218-225 ◽  
Author(s):  
Doris Orthaber ◽  
Alexander Bergmann ◽  
Otto Glatter
Keyword(s):  
Aggregation Number ◽  
Direct Method ◽  
Scattering Length ◽  
Physical Property ◽  
Absolute Intensity ◽  
Absolute Calibration ◽  
X Rays ◽  
Rotating Disc ◽  
Absolute Scale ◽  
The Absolute

For small-angle scattering, of X-rays (SAXS) and neutrons (SANS), the importance of absolute calibration has been recognized since the inception of the technique. The work reported here focuses on SAXS measurements using Kratky slit systems. In former days, only molecular weights or scattering per particle were determined, but today absolute calibration implies the use of the unit of cm−1for the scattering curve. It is necessary to measure the so-called absolute intensity, which is the ratio of the scattering intensity to the primary intensityP0. Basically there are two possible ways to determine the absolute intensity. The first one is the direct method, which involves the mechanical attenuation of the primary beam by a rotating disc or a moving slit. The second is the indirect method, using secondary standards. Water is well suited as a calibration standard because of the angle-independent scattering. The essential advantage is that the scattering of water only depends on the physical property of isothermal compressibility. Before presenting an example of the practical performance of this method, the most important theoretical equations for an SAS experiment on the absolute scale are summarized. With the slit collimation system, the scattering curve of water can be measured with high enough statistical accuracy. As a first example, the scattering curve of the protein lysozyme on the absolute scale is presented. The second example is the determination of the aggregation number of a triblock copolymer P94 (EO17–PO42–EO17). Taking into account that at least 10% of the polymer sample consists of diblocks, the accuracy of around 10% for the determined aggregation number is rather good. The data of P94 are also considered on the particle scale in order to obtain the radial scattering-length density distribution.

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