Recent Advances and New Applications of TimeResolved Xray Absorption Spectroscopy

The time-resolved x-ray absorption spectroscopy (QEXAFS) yields structural information about e.g. fast chemical decomposition reactions, thin film deposition, solid-state reactions, and phase transformations. Here we describe a new experimental set-up for QEXAFS experiments enabling the acquisition of full EXAFS spectra with a scan range of up to about 3 keV and a repetition rate of typically 10 Hz. Depending on photon flux and sample quality, repetition rates of up to 40 Hz can be used. The new monochromator design employs a fixed-exit channel cut crystal and a cam driven tilt table for rapid angular oscillations. The detection of fluorescence radiation or surface sensitive techniques can be applied. The new monochromator in combination with refractive x-ray lenses for beam focusing also allows XANES-microtomography in a reasonable time frame.