Direct Electron (United States)

The widespread establishment of cryo-electron microscopy (cryo-EM) facilities equipped with electron-counting direct electron detectors (DEDs) offers new opportunities for their application in microED experiments. Electron counting offers significant improvements in sensitivity necessary for detecting high-resolution diffraction spots. The limited linear range of most frame-based electron-counting DEDs makes them prone to coincidence loss from the higher intensity of low-resolution reflections. Recent advancements in event-based electron counting (EBEC) technology, as demonstrated by the Direct Electron Apollo detector, significantly reduce coincidence loss and allows it to capture stronger reflections without saturating (Figure 1). Apollo uses a novel event counting monolithic active pixel (MAPS) sensor with on-chip CDS and edge computing to count, upsample and sum the data within the camera hardware enabling much higher counting rates. Initial small-molecule microED experiments using the Apollo detector of sodium glutamate and histidine resolved to a remarkable 0.5 Å (Figure 2). These high-resolution datasets were acquired approximately ten times faster than those obtained with traditional frame-based MAPS detectors. Apollo's improved sensitivity and acquisition speed streamline experimental workflows and support high-throughput crystallographic screening, significantly expanding the practical applications of MicroED in structural biology and pharmaceutical research.

Journal Article Probing the Atomic-Scale Internal Phases with the Electron Beam of Mutliferroic Domain Walls Formed During Dynamics Get access Michele Shelly Conroy, Michele Shelly Conroy Department of Materials, London Centre of Nanotechnology, Henry Royce Institute, Imperial College London, UK Corresponding author: mconroy@imperial.ac.uk Search for other works by this author on: Oxford Academic Google Scholar Eoghan O'Connell, Eoghan O'Connell Max Planck Institute for the Science of Light, Erlangen, Germany Search for other works by this author on: Oxford Academic Google Scholar Kalani Moore, Kalani Moore Direct Electron, California, United States Search for other works by this author on: Oxford Academic Google Scholar Lewys Jones, Lewys Jones School of Physics, Advanced Microscopy Laboratory, Trinity College Dublin, Dublin, Ireland Search for other works by this author on: Oxford Academic Google Scholar Quentin Ramasse, Quentin Ramasse SuperSTEM, SciTech Daresbury Science & Innovation Campus, & University of Leeds, UK Search for other works by this author on: Oxford Academic Google Scholar Sinead Griffin, Sinead Griffin Molecular Foundry Lawrence Berkeley National Laboratory, USA Search for other works by this author on: Oxford Academic Google Scholar Colin Ophus Colin Ophus Molecular Foundry Lawrence Berkeley National Laboratory, USANational Center for Electron Microscopy, Lawrence Berkeley National Laboratory, USA Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 29, Issue Supplement_1, 1 August 2023, Page 1363, https://doi.org/10.1093/micmic/ozad067.699 Published: 22 July 2023

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

Before a communication link is established, spread spectrum systems must acquire the spreading PN code. The choice of code-acquisition algorithms is dictated by the trade-off of complexity and performance. A new tree-based search approach is proposed, which permits the resting of "multiple hypotheses" by utilizing the orthogonality property of the PN sequence. By defining a delayed decision mechanism and a depth dependent threshold, in the proposed approach, it is possible to permit a trade-off between the computational time required for the maximum likelihood (ML) test and the robustness lost in pure tree search.