Laboratory-scale X-ray absorption spectrometer with a cylindrical Johansson crystal analyzer

Abstract

X-ray absorption fine structure spectroscopy (XAFS) can accurately provide information on the local structure and chemical state of matter and is an important method in material research. XAFS experiments are performed at a synchrotron radiation facility. However, owing to the limited access to these oversubscribed beamtimes, it is difficult to access such large facilities for routine but important experiments. In this study, we present a laboratory-scale X-ray absorption spectrometer for XAFS measurements. The spectrometer comprises a homemade cylindrical Johansson crystal analyzer, conventional X-ray tube source, silicon drift detector, and precision Rowland circle scanning mechanism. The use of a cylindrical Johansson crystal analyzer enables the spectrometer to obtain higher energy resolution compared to a Johann-type spherically bent crystal analyzer. To demonstrate the performance of the laboratory-scale X-ray absorption spectrometer, we further measured the XAFS of 10μm thick copper foil and 5μm thick nickel, and the results were consistent with those obtained from synchrotron radiation measurements. Our results highlight that the X-ray absorption spectrometer can achieve sufficient energy resolution even at a low Bragg angle, which implies that there is no need to replace the crystal analyzers when measuring the XAFS of different samples.