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144 Result(s)
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R. Jenkins
English
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Book
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Chapter
Counting Statistics
The net intensity of emitted characteristic X-radiation from an element in a matrix is related to the concentration of that element. Fig. 5.1 illustrates the theoretical correlation between the peak intensity R ...
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Trace Analysis
Since X-ray fluorescence spectrometry is essentially a method which counts atoms, the question naturally arises as to what is the minimum number of atoms which are required in order to give a measurable signal...
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Dispersion
The basic function of the spectrometer is to provide a means of isolating a selected wavelength from the polychromatic beam of characteristic radiation excited in the sample, in order that individual intensity...
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Pulse Height Selection
Pulse height selection affords a method of isolating a moderately narrow range of wavelengths from a spectrum by virtue of energy separation as opposed to wavelength separation as, for example, in crystal disp...
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Matrix Effects
The basis of quantitative X-ray fluorescence spectrometry is to follow the identification of a certain element in a mixture of elements (the matrix) with a measurement of the intensity of one of its characteri...
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Sample Preparation
Since X-ray spectrometry is essentially a comparative method of analysis, it is vital that all standards and unknowns be presented to the spectrometer in a reproducible and identical manner. Any method of samp...
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Chapter
Physics of X-Rays
The X-ray region is normally considered to be that part of the electromagnetic spectrum lying between 0.1–100 Å, being bounded by the y-ray region to the short wavelength side and the vacuum ultra-violet regio...
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Detection
The basic problem of X-ray detection is that of converting the X-rays into a form of energy which can be measured and integrated over a finite period of time. There are numerous ways of doing this and each met...
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Chapter
Quantitative Analysis
The preceding chapters have discussed the various random and systematic errors which can arise during an analysis either from the equipment or from the sample to be analysed and it is the purpose of this secti...
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Book
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Book
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Chapter
Determination of dead time
It is necessary to determine the dead time of an X-ray spectrometer using the Kβ/Kα counting ratio method. The following data were obtained on the Kα and Kβ lines of tin by varying the X-ray tube current and k...
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Use of primary filters for removal of characteristic tube lines
It is necessary to measure low concentrations of chromium using a spectrometer equipped with a chromium anode X-ray tube. A titanium filter can be fitted over the tube window to minimize the intensity of the C...
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Detectors — double plateaux
A series of measurements are made in which counting rate is plotted as a function of counter voltage. The counter in this case is an argon/methane gas flow proportional counter. A single plateau is found for a...
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Chapter
Utilization of the ß filter and pulse height selector in diffractometry
A filter is very often used in X-ray diffractometry to reduce the background level and the intensity of β-radiation. This filter can be placed either between X-ray tube and specimen or between the specimen and...
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Count rate differences with Geiger and proportional counters
A silicon specimen is being examined using nickel filtered Cu Kα radiation. The intensities of two reflections are measured with a Geiger-Müller counter and the following counting rates obtained
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Line broadening
Measurements of the nickel (111) reflection are being made on a series of Raney Nickel catalysts. Severe line broadening problems are encountered due to the very small particle size of the powders (about 50 – ...
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Extra lines in X-ray diffractometry
A diffractometer trace is recorded of a compound known to contain a high concentration of Ba. The pattern is characterized by a very strong line with a d-spacing of 3.08Å, plus many others. A weak, broad line was...
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Chapter
Choice between fixed time and fixed count
A series of samples of alloyed steels were found to give 300 c/s/% for the Si Kα line. A calibration procedure has to be prepared over the range 0.20 – 0.60% Si and the choice has to be made between fixed coun...
