Observation of microdiffraction patterns with a dedicated STEM instrument

A two-dimensional detector system, designed for the observation and recording of microdiffraction patterns formed in an HB 5 scanning transmission electron microscopy (STEM) is described and discussed. Possibilities are described and demonstrated for the simultaneous or successive recording of microdiffraction patterns from regions of diameter 3 A or more, bright- or dark-field STEM images, EELS spectra, secondary electron images, and in-line holograms. Applications of the system have been made to studies of catalyst particles, reflection-mode imaging of bulk surfaces, and image reconstruction from microdiffraction patterns obtained from each point of a STEM image.