Ultra-High Frame-Rate Pixelated Direct Electron STEM Detector Topic 24, Subtopic a.

Multi-color electron microscopy (EM) is a powerful new technique for studying biological ultrastructure with selective lanthanide-ion tagging of specific components of interest. The technique is analogous to multi-color fluorescence microscopy, but at about 100× higher magnification. However, the current method for acquiring multi-color EM data based on energy-filtered TEM (EFTEM) requires high-priced energy-filter equipment and makes us of <1% of incident electrons, making it laborious and inefficient, often producing noisy images that are difficult to unambiguously interpret. To improve the throughput, efficiency, and resolution of multi-color EM, we are developing a new multi-color EM technique based on four-dimensional (4D) scanning transmission electron microscopy (STEM), which uses a pixelated detector to capture signals from the vast majority of the primary electrons that interact with the specimen and simultaneously record the structure and location of selective labels. Our proposed development of an ultra-fast pixelated direct electron STEM detector will make this multi-color EM fast, efficient, and greatly improve the scientific results that can be obtained, aligning well with the Department of Energy’s goal of developing powerful new tools for structural characterization of biological systems from the atomic to the cellular scale. Furthermore, our project advances the 4D STEM technique to match the speed of conventional STEM with analog detectors, which will have a broad impact on materials research. During Phase II of this project, we successfully developed and tested a new ultra-fast direct detector for 4D STEM, along with a synchronized scan controller and software for performing preliminary studies using this new hardware. The first results with biological specimens were far superior in information content and required significantly less time to acquire than would have been necessary using the previous EFTEM-based technique. However, the experimental pipeline for collecting and analyzing data to reconstruct multi-color EM structures from 4D STEM data sets remains tedious. To enable widespread adoption of this powerful new technique and ensure its commercial success, we propose to continue this project with Phase IIB by integrating our new scan control and camera into a single cohesive software package and implementing automated software for data acquisition and data analysis, leveraging high-end GPU resources to optimize experiment parameters and perform real-time data processing and reconstruction with minimal user intervention.