LABORATORY XAFS SPECTROMETER FOR X-RAY ABSORPTION-SPECTRA OF LIGHT-ELEMENTS

A new laboratory x-ray absorption fine structure (XAFS) spectrometer specially designed for measurements of the absorption spectra of light elements is presented. The spectrometer consists of a newly developed rotating-anode x-ray source of portable size, a power supply of low-voltage and high-current type, a vacuum x-ray path, a Johann-type curved monochromator, a cell unit for high-temperature measurements, and a solid-state detector (SSD) system with a single-channel analyser. The SSD system can eliminate x-rays of other orders to give x-ray absorption data containing no noise due to high frequencies. A current control method is employed to suppress characteristic x-rays emitted from filament and target materials. The performance of the spectrometer was evaluated by x-ray absorption measurements on a copper foil at the Cu K-edge at room temperature and on powdered gibbsite and aluminosilicates at the Al K-edge. The results showed that the spectrometer is capable of obtaining good quality XAFS and x-ray absorption near-edge structure (XANES) spectra at Al and Cu K-edges within about 2 h. Thus, both XAFS and XANES studies will be possible with the spectrometer for a wide range of elements from sodium to lanthanides by use of suitable monochromator crystals.