A compact-rigid multi-analyser for energy and angle filtering of high-resolution X-ray experiments. Part 2. Efficiency of a single-crystal-comb

Diffraction instruments using filtering by one or several analyser crystals exist since the 1980s and 1990s at synchrotron radiation sources, but, due to its low efficiency, this filtering is little used on laboratory sources. In order to overcome this limitation, the efficiency of a small diffraction filtering multi-analyzer block (MAD block) realized with a `single-crystal-comb' curved on a rigid support is demonstrated here. The geometry of this curved surface is logarithmic spiral and is optimized to allow multi-filtering over a relatively important diffraction angular range and to be also applicable over an X-ray spectral range. The efficiency of such a small rigid-compact MAD block consisting of this single-crystal-comb generating 20 – 50 Si(111) single-crystal blades, associated with a block of Soller collimators, is demonstrated. The angle between each crystal is 0.1 ° , so the measurement range of the comb is 2 – 5 ° . The geometry of this system has been optimized for operation with a synchrotron X-ray source over an energy range of 22   keV to 46   keV and could be used with laboratory X-ray sources (Ag   K α 1, 22.1   keV). This MAD block complements and exploits the qualities of the `photon-counting' detectors which have very low intrinsic noise. Their joint efficacy is supported by powder pattern measurements of a LaB6 reference sample and of several heterogeneous samples of cultural heritage materials, carried out at 22   keV on the D2AM beamli...
Source: Journal of Synchrotron Radiation - Category: Physics Authors: Tags: high-resolution powder diffraction multi-analyser-diffraction filtering heterogeneous materials compact-rigid multi-analyser research papers Source Type: research