Laboratory X-ray spectrometer for XAFS measurements

X-ray absorption fine structure (XAFS) is an important tool for materials information of atoms with bond length, coordination numbers and electronic state. Most of the related research has been performed at the synchrotron radiation facility for past decades. The development of conventional X-ray source and bent crystal analyzer makes it possible to conduct XAFS experiment in the laboratory. We developed a laboratory X-ray absorption spectrometer. It includes an conventional X-ray source, a Johann-type spherically bent crystal analyzer, precision Rowland circle scanning mechanism, and a silicon drift detector. The spectrometer is designed for both the X-ray absorption near-edge structure (XANES) and the extended X-ray absorption fine structure (EXAFS) analysis. The spectrometer covers the photon energy range of 8.9 - 9.6 keV and the energy resolution is about 1.2 - 3.5 eV with W anode source (spot size 0.4 mm) and Ge(800) crystal. The absorption spectrum of a copper foil with thickness of 10 mu m is measured. The result is similar to that conducted at the synchrotron radiation facility.