M.Sc. (Chemistry) / In this investigation a monostandard calibration technique was developed for multi-element X-ray fluorescence analysis. A reliable method is described for the calculation of slopes of calibration lines for thin-film and powder samples using monochromatic as well as polichromatic excitation. Theoretically calculated slopes for elements within one serles, e.g. the K-series, were normalised .using one or two known slopes for elements in the series. The mathematical equations used to -. interpolate slopes as a function of atomic number, were based on the fundamental relationship between fluorescent intensity and atomic number, fluorescent yield, detector efficiency, concentration and mass absorption coefficients. Kramer's formula was used to approximate the shape of the" primary radiation spectrum. The method was applied to the analysis of the K-series elements, with the use of thin-film and powder samples. The excitation was achieved by the use of a molybdenum-, gold-, tungsten- and chrome anodes. The method was also applied to the analysis of the L-series powder samples. The monochromatic excitation of the L-series elements, achieved with the use of a molybdenum anode, is also described. The polichromatic excitation of the L-series powder samples was obtained with a molybdenum-, gold-, tungsten- and chrome anode.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:4378 |
| Date | 18 March 2014 |
| Creators | Oosthuizen, Neil |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
| Rights | University of Johannesburg |
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