Seminar: Quantitative multi-scale imaging with dark-field x-ray microscoy\py
Presented by Assistant Professor Hugh Simons from the Department of Physics at the Technical University of Denmark
Dark-field x-ray microscopy is a new way to three-dimensionally map lattice strain and orientation in crystalline matter. It is analogous to dark-field electron microscopy in that an objective lens magnifies diffracting features of the sample; however, the use of high-energy synchrotron x-rays means that these features can be large, deeply embedded, and fully mapped in seconds to minutes. Simple reconfiguration of the x-ray objective lens allows intuitive zooming between different scales down to a spatial and angular resolution of 70 nm and 0.001°, respectively. Three applications of the technique are presented: the evolution of subgrains during the processing of plastically deformed aluminum, the reconfiguration of domains and their strain fields in ferroelectric crystals, and the three-dimensional mapping of lattice distortions around individual dislocations. This ability to directly characterize complex, multiscale phenomena in-situ is a key step toward formulating and validating multiscale models that account for the entire heterogeneity of materials
Hugh Simons is an Assistant Professor at the Department of Physics at the Technical University of Denmark. He received his B.Eng. (2009) and Ph.D. (2013) in Materials at the University of New South Wales. From 2013-15, he was a postdoctoral researcher at the European Synchrotron Radiation Facility, before completing a postdoctoral fellowship sponsored by the Danish Council for Independent Research at the Technical University of Denmark from 2015-17. His research intersects materials science and microscopy through the development of novel x-ray and neutron-based methodologies for the quantitative, multi-scale 3D imaging of materials. In particular, he focuses on defects and interfaces in multifunctional oxides including piezoelectrics, ferroelectrics and multiferroics.