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.

For more details on multigrain crystallography in the diamond anvil cell, you can check:

• 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: 10.1107/S1600576716018057]
• 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: 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: 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), abstract [doi: 10.1080/08957959.2014.885021]