Abstract
Comparisons between the thin and thick target methods of measuring proton-induced K X-ray production cross-sections have been made. It was concluded that the thin target technique is superior. Cross-sections for the production of K X-rays from thin targets of selected elements in the range Z = 22-34 have been measured with absolute uncertainties of +/- 5 % for the case of irradiation with light ions (Z ≤ 2) of energy 1-3 MeV. K shell ionization cross-sections have been deduced from these measurements and a modification of the Semi-Classical Approximation fitted to the resulting data. Fitted values for the ionization cross-sections for protons have been generated for all targets with Z = 18-50; uncertainties being as low as +/- 5 % in the region Z = 22-34. The value of these results for use in particle-induced X-ray emission (PIXE) analysis and in comparisons between the various theories of inner shell ionization is discussed. A detailed description is given of the apparatus and experimental techniques; especially the methods of measuring ion beam fluence, X-ray detection efficiency and target mass thickness. For each of these cases, significant advances over the more commonly used methods are reported. The principles, history and present status of PIXE analysis are outlined and comparison made with other methods of producing characteristic X-rays. The technique has been applied to the study of time-resolved deposits of air particulate pollution. Details are given of the air sampling technique and the application of PIXE and electron microprobe X-ray analysis to the characterization of these samples. Analyses of a widely varying selection of other types of sample were performed and conclusions drawn on the suitability of the technique for these cases. Finally, conclusions are drawn on the achievements of the work and suggestions for future studies are given.