Development of Fast Direct Detectors for 4D STEM, In Situ TEM, and Other Applications

Advanced transmission electron microscopy (TEM) techniques such as four-dimensional scanning TEM (4D STEM), and <i>in situ</i> TEM, require detectors with fast imaging speeds and single-electron sensitivity. Direct Electron has recently developed new fast direct detectors to meet the needs of these advanced applications.<br/> <br/>Celeritas and Celeritas XS are 1024 x 1024 pixel detectors that are designed for extremely high frame-rate readout. The Celeritas XS detector can generate images at speeds of up to 87,000 frames per second, when reading out a small central region. For applications such as 4D STEM, this allows high-throughput data collection at speeds approaching conventional 2D STEM. Celeritas XS has recently applied to study the local ordering in amorphous materials such as molecular glasses [1], and metallic glasses [2]. When coupled with a programmable DE FreeScan scan generator, these detectors can be used to explore novel scanning techniques to collect data more efficiently.<br/> <br/>The Apollo detector is a 4096 x 4096 pixel detector that has, to date, primarily been used for biological TEM imaging applications [3,4]. Apollo may also be promising for TEM imaging of beam sensitive materials such as polymers. Apollo uses a unique event-based readout method [5] to generate electron counting images with greater data efficiency than previous frame-based detectors, which helps to minimize coincidence loss, maximize detective quantum efficiency, and reduces the detector’s cost.<br/> <br/>Here, we will discuss the development of these detectors and a variety of potential applications, including 4D STEM and in situ TEM.<br/> <br/>References:<br/>[1] Chatterjee et al. <i>Nano Lett.</i>, <b>23</b>, 5, 2009–2015 (2023)<br/>[2] Huang et al. <i>Ultramicroscopy</i>, <b>241</b>, 113612 (2022)<br/>[3] Peng et al. <i>J. Struct Bio X</i>, <b>7</b>, 100080 (2023)<br/>[4] Bhella et al. Data DOI: 10.6019/EMPIAR-11404<br/>[5] Levin et al. <i>Microscopy & Analysis</i>, January Issue, 15-17 (2023)