Introducing a non-pixelated and fast centre of mass detector for differential phase contrast microscopy

Four-Dimensional Scanning Transmission Electron Microscopy (4D-STEM): From Scanning Nanodiffraction to Ptychography and Beyond

“…One advantage of DPC relative to more complex 4D-STEM measurements is that it reduces the measurement data of each probe to a very small number of variables such as the COM displacement vector. This allows fast alternatives to pixelated detectors to be used for DPC measurements, such as the previously mentioned segmented or delay-line detectors, or a duo-lateral position sensitive diode detector which can read out the COM of the probe as opposed to a full image, such as in Schwarzhuber et al (2018). It may also be possible to use pixelated 4D-STEM detectors in combination with dedicated hardware directly after the detector pixels such as a field-programmable gate array, to perform simple measurements such as DPC (Johnson et al, 2018).…”

Comparison of first moment STEM with conventional differential phase contrast and the dependence on electron dose

“…In particular, the speed of seg-mented detectors is up to two orders of magnitude higher than that of available ultrafast cameras, and the FM-STEM requires partly advanced analyses of large fourdimensional data sets. However, recent improvements of the efficiency of data processing, e.g., in the LiberTEM project [45], or the introduction of ultrafast, non-pixelated, direct first moment detectors [46] are encouraging developments that have the potential to enhance the practical applicability of first moment STEM to that of sDPC and conventional STEM imaging. Consequently, first moment STEM currently takes the step to become a valuable technique for quantitative differential phase contrast imaging beyond the weak phase approximation and hence complements the range of applications of DPC STEM.…”

Robust Atomic-Resolution Imaging of Lithium in Battery Materials by Center-of-Mass Scanning Transmission Electron Microscopy

“…While segmented detectors allow rapid data acquisition, current state-of-the-art pixelated detectors operate fast enough to produce high-quality data and offer many advantages critical for producing reliable images, such as allowing the true CoM to be measured, significantly simplifying the experimental setup since no precise beam–detector alignment is required and providing the flexibility to optimize results by adjusting parameters such as collection angle in postprocessing. In addition, the next generation of pixelated detectors is currently under development and will allow even more rapid data acquisition. − The analysis of pixelated detector data is also relatively straightforward (see the Supporting Information) and thus will eventually allow on-the-fly data processing by taking advantage of rapidly developing open-source computational methods. , Finally, a detector that enables the CoM to be directly measured without recording a diffraction pattern has also recently been developed and enables measurements at speeds comparable to segmented detectors . While this type of detector provides a good compromise between pixelated and segmented detectors, pixelated detectors provide the most flexibility, for example allowing conventional STEM images to be simultaneously reconstructed from the data, and their acquisition speeds are increasing rapidly, − as mentioned above.…”

“…49,50 Finally, a detector that enables the CoM to be directly measured without recording a diffraction pattern has also recently been developed and enables measurements at speeds comparable to segmented detectors. 51 While this type of detector provides a good compromise between pixelated and segmented detectors, pixelated detectors provide the most flexibility, for example allowing conventional STEM images to be simultaneously reconstructed from the data, and their acquisition speeds are increasing rapidly, 45−48 as mentioned above. For these reasons, we focus here on DPC measured using a pixelated detector, or CoM-STEM.…”