A High Precision Calculation of the Excitation Flux for X-ray Fluorescence Spectroscopy with Cylindrical Geometry

Radioisotope-excited X-ray fluorescence is one of the more recent techniques developed that has resulted from the general availability of sealed radionuclide sources. In experimental work, following the excitation of the specimen by X-ray photons, the integrated photo-peak intensity of the characteristic fluorescent line of interest is measured and usually compared with the results of theoretical estimates. Experimental results can be obtained with higher precision due to recent developments in solid state detectors and in the use of computers [1-4]. However, owing to the complexity of the overall exact calculation for X-ray fluorescence systems of given dimensions, theoretical estimates are found to be not of the same precision as that of the experimental results. Prior to reaching the final theoretical estimates of detector count rate, a prerequisite calculation of essential parameters, such as excitation flux and fluorescent intensity variation over the specimen, are required.