High-Throughput 4D-STEM via Electrostatic Subframing

Four-dimensional scanning transmission electron microscopy (4D-STEM) is a powerful and fast-developing set of methods for extracting unprecedented depths of nanoscale structural information from materials. 4D-STEM is an incredibly flexible tool that acts as an enabling technology for nanoscience, biomaterials study, energy materials development, and many other uses. However, it is extremely demanding in terms of information throughput, practically necessitating a camera that can operate at thousands of frames per second. Such cameras are rare, expensive, and still limited in their frame rates. There is strong demand both for even faster cameras and for technology that could allow older microscope facilities to access advanced 4D-STEM capabilities using their existing cameras. Electrostatic subframing (ES) is a method for subdividing a camera into a large number of parallel-acquiring subframes, allowing existing conventional cameras to reach the extreme frame rates of much more expensive cameras. When applied to an already-fast camera, ES allows even higher performance, at the level of 100,000 frames per second or more. ES further improves frame rates through compressive-sensing and adaptive-scanning techniques, intelligently spending electrons and acquisition time to learn all of the relevant information about a material as quickly as possible. Combined into an advanced data analysis suite, ES-4D-STEM promises to bring 4D-STEM to a broad class of researchers while simultaneously enhancing the performance of even the most high-end systems. IDES has already developed an ES system for in situ experiments, but 4D-STEM carries unique system integration and data analysis challenges requiring specific development. Phase I is a tightly-integrated set of tasks aimed at producing the algorithms, software, system designs, and (using simulation) expected performance enhancement for ES-4D-STEM (including compressive and adaptive variants) needed to produce a functional prototype early in Phase II. This project will bring the extremely powerful capabilities of modern 4D-STEM within reach of any STEM user while simultaneously pushing the performance of top-end systems to currently unattainable levels. 4D-STEM provides uniquely detailed information on material structure from the atomic scale to the micrometer scale. It has enormous applicability for university, national laboratory, and industrial users in materials science, chemistry, biomaterials, and many other areas.