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ECRYS-2005, Cargèse France PowerPoint Presentation
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ECRYS-2005, Cargèse France

ECRYS-2005, Cargèse France

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ECRYS-2005, Cargèse France

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  1. LAUE DIFFRACTION: The key for NEUTRON DIFFRACTION from submillimetric SINGLE CRYSTALS  The new Laue diffractometer VIVALDI at the ILL M.H. L-C1, G.J. McIntyre1 and C. Wilkinson1,2 1 Institut Laue-Langevin, Grenoble France 2 Chemistry Dept, Durham University UK ECRYS-2005, Cargèse France

  2. Zr Neutron high pressure cells (courtesy of L. Melesi) Neutron diffraction: - no charge - spin ½ - energy few meV But very low flux (/RX)  Laue diffraction is a necessary tool for modern structural studies requesting neutron! Ti Why scientists need LAUE NEUTRON DIFFRACTION ? Actual trends in condensed matter research: - New materials with more and more highly sophisticated composition  chemical contrast (H, light elts…)  delicate synthesis - Magnetism - Complex external conditions (high pressures, very low temperatures …) - Out of equilibrium phenomena With interest for structural properties but also for electronic properties, The coupling between both appearing to be more and more crucial, Indeed it has appeared in the last decade that it is more interesting to look to non-linear interaction which have the advanteg to enhance in a much more efficient way properties (inetrest for the potential applications with materiels wich can be able to excute different tasks with a much smaller amount of energy) ECRYS-2005, Cargèse France

  3. single crystal Copper sulfate white X-ray beam 2D detector M. von Laue, Nobel Lecture Stockholm (1915) Detection of X-ray interferences - white beam diffraction technique - Fixed 2-dimensional detector - single crystal ECRYS-2005, Cargèse France

  4. 1/min (hkl) (2h2k2l) (hkl) 2 2 1/2 min 1/max Singles, overlap included All singles and multiples, overlap included multiples, overlap included Fundamentals of Laue diffraction: - white beam diffraction technique - fixed detector - single crystal Problem of multiple scattering but not for ~ 83% of spots (with min <  < 2min) Ewald sphere Multiple scattering but not for ~ 83% of spots (with min <  < 2min) Laue suite http://www.ccp4.ac.uk/main.html ECRYS-2005, Cargèse France

  5. OrientExpress Laue diffraction: white beam  end position on neutron guide - LADI: for proteins (cold neutrons ) - VIVALDI: Very Intense Vertical Axis Laue DIffractometer - OrientExpress: crystal testing instrument (historical neutron Laue diffractometer J.C. Marmeggi) ECRYS-2005, Cargèse France

  6. Laue diffraction pattern of incommensurate La2Co1.7 - within a day of the first neutrons (G. McIntyre et al) VIVALDI: Very Intense Vertical Axis Laue DIffractometer - white beam for maximum flux - thermal neutron for maximum reflectivity (0.8 <  < 5.2Å) - large image plates (Gd2O3 in BaFBr:Eu2+) for 8 sterad (288° horizontally x 104° vertically) - high resolution (200x200m2) and large dynamics range (108) - vertical geometry to allow complex sample environments factor 10 to 100 gain over monochromatic data collection (as fast as powder diffraction!)  possibility to study small crystals ECRYS-2005, Cargèse France

  7. Zoom-in on part of the observed pattern Quick inspection of integration ellipsoid boundaries Predicted Laue pattern superimposed Spots are tomographic projections of the crystal Improvements needed for spatial overlap Data reduction of conventional structures (mostly) by programs of the CCP4 X-ray Laue suite www.dl.ac.uk/SRS/PX/jwc_laue/laue_top.html ! Cell parameters: known from e.g. powder diffraction Vitamin B12 ~10 000 reflections in each 8-hour exposure, mean I/(I)= 10, 6 mm3 crystal G. McIntyre, S. Mason, Wagner, Luger ECRYS-2005, Cargèse France

  8. Compound Volume (mm3) Unitcell (Å3) Expose (hr) No. Peaks I/s(I) Total (hr) Vitamin B12 6 8853 2 7596 10.1 60 Cs3VCl6.4H2O 2 446 0.7 647 6.6 3 Na2Pb(OH)2 2 147 0.8 263 7.9 5 LiAlSi2O6 1.4 389 0.33 442 11.9 2 Co(NH3)6.CuCl5 1 2691 0.7 1865 6.0 3 Co4C22H36 0.6 8254 2.5 4340 4.8 22 dabcoHBF4 0.21 473 1 384 5.0 10 C4H4N2O2 C26H32FeN9O2S4 0.00075* 0.2 451 3293 2 4 272 2786 1.1 5.0 16 48 First experiments on VIVALDIVery fast data collection over all of reciprocal space for very small samples *10 kbar TiZr pressure cell !! ECRYS-2005, Cargèse France

  9. Concluding remarks: You want to have precise informations (light elements…) You want to work under complex environment conditions (high pressure, very low temperature, magnetic field…) Neutron diffraction can do a lot for you even if you do not have large single crystals ! ECRYS-2005, Cargèse France

  10. ECRYS-2005, Cargèse France