The density and tube energy dependency of cobalt Kα/Kβ in x-ray fluorescence spectrometry for thick target measurements

The relative intensity of K-alpha/K-beta for cobalt in thick targets with cobalt mass densities from 0.51 to 22.49% has been measured by the wavelength dispersive x-ray fluorescence (XRF) spectrometer. The measuring conditions are: tube current ranging from 1.0 to 60 mA and voltages ranging from 20 to 60 kV. We plotted the K-alpha/K-beta ratio vs Co densities for different tube voltages and currents. Our study shows that the K-alpha/K-beta ratio is below the theoretical value for low Co densities and it increases with increasing Co density. For higher x-ray energies, the K-alpha/K-beta ratio shows a sharp growth at the special density and then reaches a nearly constant value. However, K-alpha/K-beta ratio is theoretically constant and independent of energy in thin target measurements. The changes of this ratio according to the x-ray energy and the element density have been studied in thick target measurements. The results provide experimental evidence to suggest that exciting energy and element density can indeed affect the K-alpha/K-beta ratio. Copyright (c) 2008 John Wiley & Sons, Ltd.