Absolute Determination of Characteristic X-Ray Yields with a Wavelength-Dispersive Spectrometer

We describe a method to determine characteristic x-ray yields in absolute units with a wavelength-dispersive spectrometer. The method requires measurement and calculation of the thick-target bremsstrahlung intensity emitted from a reference sample at the photon energy of interest. Bremsstrahlung intensities are calculated by using the general-purpose Monte Carlo simulation code PENELOPE. We discuss the different sources of uncertainty and apply the developed methodology to the determination of absolute x-ray yields emitted from (i) thick samples, (ii) thin films on substrates and (iii) ultra-thin, self-supporting films. We compare measured yields with the predictions of theoretical/analytical calculations and Monte Carlo simulation, and whenever possible, with similar measurements found in the literature.