A bent Laue analyzer detection system for dilute fluorescence XAFS.

An analyzer for detection of fluorescence radiation has been developed for XAFS of dilute samples in the 15–25keV range. The analyzer is a thin bent Laue crystal of logarithmic spiral shape held in a machined frame. A large solid angle of k fluorescence lines can be collected with moderate reflectivity using the asymmetric [111] reflection of a silicon crystal 200 microns thick. The crystal (35mm by 120mm active area) covers a solid angle of 0.1 sr of the sample fluorescence. A set of Soller slits to match the virtual x-ray source and reject scatter were designed and fabricated. Experiments were performed at the APS BioCAT and MRCAT ID beamlines using silver fluorescence x-rays. Measurements of the performance of this device and plans for a detection system are presented. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]