Electron detection with CdTe and GaAs sensors using the charge integrating hybrid pixel detector JUNGFRAU

Abstract

Speed, dynamic range, and radiation hardness make hybrid pixel detectors suitable image detectors for diffraction experiments. At synchrotrons and X-ray free electron lasers they are ubiquitous. However, for electron microscopy their spatial resolution is limited by multiple scattering in the sensor layer. In this paper we examine the use of two high Z sensor materials: CdTe and GaAs, as a way to mitigate this problem. The sensors were bonded to a JUNGFRAU readout chip which is a charge integrating hybrid pixel detector developed for use at X-ray free electron lasers. Using in-pixel gain switching, it can detect single particles down to 2 keV while maintaining a dynamic range of 120 MeV/pixel/frame. The characteristics of JUNGFRAU, besides being a capable detector, make it a good tool for sensor characterization since we can measure dark current and energy deposition per pixel. The high Z material shows better spatial resolution than silicon at 200 and 300 keV, however, their practical use with integrating detectors is still limited by material defects.

Machine learning for classifying narrow-beam electron diffraction data

“…In addition, the number of applications in transmission electron microscopy (TEM) is growing (Treder et al, 2022;Yonekura et al, 2021). The emergence of direct electron and hybrid pixel detectors (HPDs) (Fro ¨jdh et al, 2022; has changed the cryo-EM (cryo-electron microscopy) field significantly (Faruqi & McMullan, 2018). If combined with advanced data collection and analysis techniques, this could enable structural biologists to reveal the structure of complex biomolecular machines at near-atomic resolution.…”

“…By assuming the beam is not much wider than the size of the protein of interest, this approach is likely to improve the signal-to-noise ratio compared with cryo-EM imaging (Latychevskaia & Abrahams, 2019). HPDs have proven to be better for these types of data than the direct electron detectors used for cryo-TEM (Fro ¨jdh et al, 2022). With more than 1000 frames per second and a high dynamic range, data collection pipelines need to cope with rates of up to 10 Gb s À1 during multi-minute runs for just 512 Â 512 pixels.…”