Figure 8
Single-crystal-comb MAD block having 50 Si(111) crystals working in reflection mode to filter powder diffraction patterns. (a) This silicon single-crystal-comb was cut to generate Si(111) planes 1.7 mm apart. Its single-crystal framework is perforated underneath and has a small thickness at the crystal junction (0.7 mm) to allow a few degrees of bending without generating stresses inside the Si(111) crystal blades. (b) Photograph of the single-crystal-comb block made by 3D printing that imposes the LogSpiral curvature to the silicon single-crystal-comb; it is mounted on the ΘA arm of the diffractometer. (b′) Photograph of the 3D printed Soller-collimator block containing 51 collimator blades. It is mounted on the 2ΘA arm of the diffractometer after the single-crystal-comb block and before the 2D detector. (c) Scheme with 46 keV X-rays (ΘA = 2.4632°) of 11 paths of the 50 beams (spaced by 0.1°) and filtered by this rigid compact analyser block associated with the Soller-collimator block. (d) Example of intensities collected on the XPAD 2D detector during a 2Θ scan of the detector arm: they highlight the diffraction signal filtered by this single-crystal-comb with an angular pitch of 0.1° between each Si(111) crystal. (d′) Definition of the small reception windows on the detector for three analyser crystals (Nos. 1, 6, 13) with an example of the intensities collected with a 0.002° step. |