====== Multigrain crystallography in the diamond anvil cell ======

Multigrain crystallography allows characterizing hundreds of crystals in a polycrystalline material. It has been adapted to diamond anvil cell experiments for the investigation of materials under high pressure and high temperature. Simulations have shown that the method allows to index up to 500 grains with a theoretical resolution of 0.02° in grain orientation (Langrand et al, 2017).

The TIMEleSS group at the Université de Lille has been involved early on with multigrain crystallography (Nisr et al, 2012). Recently, it focused on the study of transformation microstructures, which is at the foundation of the TIMEleSS project.

TIMEleSS publications relying on multigrain X-ray crystallography
  * J.P. Gay, E.E. Ledoux, M. Krug, J. Chantel, A. Pakhomova, C. Sanchez-Valle, S. Speziale, S. Merkel, Depth Dependent Deformation and Anisotropy of Pyrolite in the Earth’s Lower Mantle, //Geophysical Research Letters//, **51**, e2024GL109433 (2024) [doi: [[https://doi.org/10.1029/2024gl109433 | 10.1029/2024gl109433]]]
  * E E. Ledoux, M. Saki, J. P. Gay, M. Krug, O. Castelnau , W.-Y Zhou, J. S. Zhang, J. Chantel, N. Hilairet, M. Bykov, E. Bykova, G. Aprilis, V. Svitlyk, G. Garbarino, C. Sanchez-Valle, C. Thomas, S. Speziale, and S Merkel, Deformation mechanisms, microstructures, and seismic anisotropy of wadsleyite in the Earth’s transition zone, //Geochemistry, Geophysics, Geosystems// **24** e2023GC011026 (2023) [doi: [[https://doi.org/10.1029/2023gc011026 | 10.1029/2023gc011026]]] 
  * E. Ledoux, M. Krug, J. Gay, J. Chantel, N. Hilairet, M. Bykov, E. Bykova, G. Aprilis, V. Svitlyk, G. Garbarino, N. Guignot, C. Sanchez-Valle, S.  Speziale, and S. Merkel, In-situ study of microstructures induced by the olivine to wadsleyite transformation at conditions of the 410 km depth discontinuity, //American Mineralogist// in press (2023) [doi: [[https://doi.org/10.2138/am-2022-8731 | 10.2138/am-2022-8731]]].
  * J. P. Gay, E. Ledoux, M. Krug, J. Chantel, A. Pakhomova, H.-P. Liermann, C. Sanchez-Valle, and S. Merkel. Transformation microstructures in pyrolite under stress: Implications for anisotropy in subducting slabs below the 660 km discontinuity //Earth and Planetary Science Letters// **604** 118015 (2023) [doi: [[https://doi.org/10.1016/j.epsl.2023.118015 | 10.1016/j.epsl.2023.118015]]]
  * M. Krug, M. Saki, E. Ledoux, J. P. Gay, J. Chantel, A. Pakhomova, R. Husband, A. Rohrbach, S. Klemme, C. Thomas, S. Merkel, C. Sanchez-Valle. Textures induced by the coesite-stishovite transition and implications for the visibility of the X-discontinuity. //Geochemistry, Geophysics, Geosystems// **23** e2022GC010544 (2022) [doi: [[https://doi.org/10.1029/2022GC010544 | 10.1029/2022GC010544]]]

Prior publications from the group on multigrain crystallography in the diamond anvil cell:
  * C. Langrand, N. Hilairet, C. Nisr, M. Roskosz, G. Ribárik, G.B.M. Vaughan, S. Merkel, Reliability of Multigrain Indexing for Orthorhombic Polycrystals above 1 Mbar: Application to MgSiO3-Post-Perovskite, //Journal of Applied Crystallography//, **50**, 120-130 (2017) [doi: [[http://dx.doi.org/10.1107/S1600576716018057|10.1107/S160057671601805]]7]
  * A. D. Rosa, N. Hilairet, S. Ghosh, J.-P. Perrillat, G. Garbarino, S. Merkel, Evolution of grain sizes and orientations during phase transitions in hydrous Mg2SiO4, //Journal of Geophysical Research: Solid Earth//, **121**, 7161–7176 (2016) [doi: [[http://dx.doi.org/10.1002/2016JB013360|10.1002/2016JB013360]]]
  * A. D. Rosa, N. Hilairet , S. Ghosh, G. Garbarino, J. Jacobs, J.-P. Perrillat, G. Vaughan and S. Merkel, In situ monitoring of phase transformation microstructures at Earth's mantle pressure and temperature using multi-grain XRD, //Journal of Applied Crystallography//, **48**, 1346-1354 (2015) [doi: [[http://dx.doi.org/10.1107/S1600576715012765|10.1107/S1600576715012765]]]
  * C. Nisr, G. Ribárik, T. Ungár, G. B.M. Vaughan, S. Merkel, Three-dimensional X-ray diffraction in the diamond anvil cell: application to stishovite, //High Pressure Research//, **34**, 158-166 (2014)[doi: [[http://dx.doi.org/10.1080/08957959.2014.885021|10.1080/08957959.2014.885021]]]
  * C. Nisr, G. Ribárik, T. Ungár, G. B. M. Vaughan, P. Cordier, S. Merkel, High resolution three-dimensional X-ray diffraction study of dislocations in grains of MgGeO3 post-perovskite at 90 GPa, //Journal of Geophysical Research//, **117**, B03201 (2012) [doi: [[http://dx.doi.org/10.1029/2011JB008401|10.1029/2011JB008401]]]