Harmonics as an alternative method for measuring I0 during x-ray absorption spectroscopy experiments at laboratory scale.

Abstract

In the recent years, the advent of an efficient and compact laboratory-scale spectrometer for x-ray absorption spectroscopy experiments has been extensively reported in the literature. Such modern instruments offer the advantage to routinely use x-ray absorption spectroscopy on systematic studies, which is usually unconceivable at synchrotron radiation source facilities due to often limited time access. However, one limiting factor is the fact that due to laboratory x-ray source brightness compared to a synchrotron, two separate measures of the incoming and transmitted x-ray intensities, i.e., the so-called I0 and I1, respectively, are usually required. Herein, we introduce and discuss an alternative approach for measuring I0 and I1 simultaneously. Based on the usage of harmonics arising naturally from the use of monochromator crystals, the reliability and robustness of our proposed approach is demonstrated through experiments at the Co K-edge measured using Co metal foil and at the Nd L3-edge measured in Nd2O3.