Quantitative element analysis with an energy dispersive X-ray fluorescence instrument equipped with a highly oriented pyrolytic graphite filter

We present an energy-dispersive X-ray fluorescence (EDXRF) instrumentation mainly intended for the quantitative analysis of actinides based on their intense L X-ray lines. The experimental setup is equipped with a highly oriented pyrolytic graphite (HOPG) optic as a bandpass filter placed between a sample and a detection system. In such an arrangement, it modifies the spectral distribution of the fluorescence radiation and allows recording of a spectrum in the energy range from 10 keV to 18 keV, while suppressing parts considered to be useless. In order to perform accurate quantitative analysis of the recorded spectra, the classical quantification algorithm based on the fundamental parameters must be adapted to take into account the effect of the HOPG optic on the measured intensities. This requires to determine the transmission function of the HOPG filter and implement it in the algorithm. The validity of this approach is checked in different application examples.