59 Result(s)
within
English
R. Jenkins
Physics
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Chapter
Estimation of error introduced by ignoring the background
Whenever X-ray intensity measurements are made on a selected peak, occuring at a certain setting of the goniometer, some fraction of the measured counting rate is always due to background. The significance of ...
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Variation of limit of detection with analysis time
A series of measurements of fluorine in cement sample yielded a peak counting rate of 4 c/s/% for fluorine (F Kα) over a background of 6.5 c/s.
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Continuous radiation — Scattered radiation
The continuous radiation from an X-ray tube is scattered by the sample, diffracted by the analyzing crystal and measured by the detector.
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Particle statistics in X-ray diffractometry
Only those crystallites having the reflecting planes almost parallel to the specimen surface can contribute to a certain reflection. The intensity of the resulting diffraction is thus dependent on this number ...
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Dispersion as a function of ‘d’ spacing
LiF is commonly used as an analysing crystal. The (200) reflection planes are commonly used, having a “2 d” value of 4.028 Å. It is, however, possible to use reflecting planes with other Miller indi...
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Determination of CaO in cement (ratio measurement)
The following data were obtained using a series of cement samples. Counting ratios were determined on the Ca Kα line using sample 5 as the ratio standard.
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Absorption correction involving primary and secondary absorption
The slope of a calibration curve for a certain element is dependent upon the total absorption of the measured wavelength within the sample matrix. Although it is common practice to assume that only secondary a...
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Pulse height selection — crystal fluorescence
It is necessary to set up an X-ray spectrometer for the measurement of sodium in a series of rock specimens. An argon/methane flow counter is being employed and a KAP (potassium hydrogen phthalate) analysing c...
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Calculation of matrix absorption and prediction of absorption effects
The total secondary absorption of a matrix is given by
(16) $$\mu_{matrix} = \sum\limits_i {\left({\mu_i w_i} \right)\left({16... -
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Use of α correction factor (intensity correction)
A series of eight samples were analysed for a certain element A. An element B, also present in major concentration, was found to strongly absorb element A.
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Excitation probability
It is often thought that the wavelength in the primary spectrum most efficient in exciting the fluorescent radiation of an element A is that which is closest to the absorption edge of element A. The probabilit...
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Quantitative X-ray diffractometry use of internal standard
The weight fraction of α quartz (SiO2) has to be determined in a natural specimen. To correct for the unknown absorption in this specimen, 200mg KC1 are added to 1000 mg of the sample, both very finely, ground, a...
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Estimation of gold plating thickness
The following intensities were obtained from a series of gold plated steel samples measured on the Au Lα line.
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Quantitative x-ray diffractometry
Very often the quantity of a compound has to be determined in a complex mineral, the composition and absorption coefficients of which are unknown. To correct for these unknown facts, the attenuation of a diffr...
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Background variation
A scan is being made on a rock sample in the region of the barium K spectra.
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Calculation of ß filter thickness and transmission
A Ni filter has been constructed in such a way that only 2% of the incident Cu Kβ radiation may pass. Given that the density of Ni is 8.92 g/cm3 and that the mass absorption of Ni for Cu Kα and Cu Kβ is 49.2 cm2/...
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Choice of detectors
A A choice has to be made between the scintillation counter and the flow proportional counter for the measurement of a certain wavelength.
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Determination of lattice constants for a cubic lattice
The following 12 lines were obtained from a crystalline powder. Data were obtained using nickel filtered Cu Kβ radiation. The powder is known to belong to the cubic system.
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Dispersion of the diffractometer
The dispersion of the diffractometer (dθ/dλ) can be expressed in the given form obtained by differentiating the Bragg law nλ = 2dsinθ
(5) ... -
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Spurious peaks in X-ray diffractograms
Adiffractogram of quartz exhibited an additional spurious peak at approximately 6° (2θ).The effect was observed both in specimens containing only low atomic number elements and specimens containing high atomic...
