Gems Tutorial: Simulating Diffraction Patterns

This lecture introduces the use of the GEMS software for simulating diffraction patterns in materials science. The instructor begins by reviewing previous topics in diffraction theory, including kinematical and dynamical scattering. The tutorial focuses on practical applications of GEMS, demonstrating how to navigate the software and select crystal structures, specifically aluminum. The instructor explains the importance of parameters such as camera length and acceptance angle in diffraction simulations. Various settings are adjusted to visualize 3D projections and diffraction patterns, emphasizing the significance of crystal thickness and the interaction of beams. The lecture also covers advanced topics like two-beam simulations and the impact of structural polarity on diffraction patterns. Throughout the session, the instructor addresses common issues users may encounter, providing troubleshooting tips. The tutorial concludes with a discussion on the relationship between simulation parameters and experimental results, highlighting the complexities of high-resolution transmission electron microscopy (HRTEM) and the importance of accurate simulations in understanding material properties.