XANES REGISTRATION BY ELECTRON-BEAM POSITION SCANNING FOR TIME-RESOLVED EXPERIMENT

A new method of XANES registration has been designed and realised at V EPP-3. Traditionally, the monochromator rotation is used for the energ y scanning. In this new method, the position of the monochromator is f ixed, but the position of the electron beam is changed by the magnetic field. As a result, the angle SR-beam/monochromator is changed thus c hanging the energy of the monochromatic beam. We registered test-XANES spectra of Ag by electron beam position scanning and then used this m ethod to investigate fast Ag reduction from organometallic compounds. Depending on the type of monochromator and on the energy interval, XAF S spectra may be measured now within 6-20 s. Traditional QEXAFS has a natural limit, depending on the mass of the crystal of the monochromat or, holder and translation stage. The mass of the electrons in the bun ch is very small and there is no limit for fast scanning. The use of a n undulator as synchrotron radiation source can improve the time resol ution of this method by several orders of magnitude and reach nanoseco nd region.