A new approach for in-laboratory XAFS equipment

A so-called linear spectrometer with bent-crystal has been usually used for an in-laboratory EXAFS apparatus, because of its high efficiency of utiliz ing X-rays from an ordinary X-ray tube and its better energy resolution. In a linear spectrometer, the monochromator crystals have to be aligned very accurately along a Rowland circle, so the goniometer movement becomes very complicated. The mechanism of the monochromator can be very much simplified when parallel X-rays are used. We propose to use polycapillary optics to o btain a quasi-parallel X-ray beam from a conventional X-ray source and meas ure EXAFS spectra by a simple system utilizing an ordinary powder diffracto meter.