EDET DH80k - characterization of a DePFET based sensor for TEM direct electron imaging

Abstract In recent years, commercially available camera systems for transmission electron microscopy have greatly improved their spatial resolution, whereas temporal resolution was side tracked due to it being non-essential in the imaging of stationary objects. Consequently, a system needed for investigation of dynamic processes, e.g. protein folding, is not yet available. Therefore, the EDET DH80k camera system with a full frame readout frequency of 80 kHz for a 1 Mpixel array is in development. Optimization steps were taken to improve spatial resolution by minimizing the impact of the multiple- and back-scattering of primary electrons. This is achieved by back-thinning of the sensor volume, removal of support layers and an optimized beam dump. With DePFET technology, a dynamic range of a minimum of 8 × 105 signal e − per pixel is achieved. An in-pixel signal compression is implemented by means of a nonlinear response function. Therefore, the sensitivity to single primary electrons as well as Poisson-limited sensitivity to numbers of 100 and more primary electrons is realized. In this paper, characterization measurements of the final pixel design are presented.