Electron crystallography has gained a significant impact and interest over the last few years due to the development of 3D data acquisition techniques and analysis of the obtained 3D Electron diffraction data1. The introduction of new, direct detectors provided a significant boost to the speed and data quality of 3D ED data. However, a direct comparison of the data quality coming from these new detectors and from more traditional detectors has rarely, if ever, been made on real-life data. Therefore, we decided to profit from our microscope setup, which allows easy switching between two detectors, and compare the data collection techniques (Continuous rotation and Precession) and structure refinement under almost identical conditions.
The analysis was done on a TEM FEI Tecnai G2 20 with an accelerating voltage of 200 kV, equipped with a CCD detector Olympus SIS Veleta, dynamic range 14 bit, and hybrid pixel detector Medipix 3 ASI Cheetah. Both detectors are retractable, mounted at the same height at opposite side-entry ports of the microscope, having an almost identical field of view. Therefore, data can be collected on both without changing any alignment settings of the microscope. The data was collected from three inorganic materials and one organic material.
All the data sets were processed with PETS22 software and the structure was then solved and refined in JANA20203 using dynamical refinement. In the seminar, I will talk briefly about my ongoing work on improving data processing and structural refinement techniques for 3D ED data by giving insight into frame scaling during data processing and more about absolute structure determination using dynamical refinement.

References
[1] Gemmi, M., Mugnaioli, E., Gorelik, T., Kolb, U., Palatinus, L., Boullay, P., Hovmöller, S. & Abrahams, J. (2019). ACS Cent. Sci. 5, 1315– 1329.
[2] Palatinus, L., Brázda, P., Jelínek, M., Hrdá, J., Steciuk, G., & Klementová, M. (2019). Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials, 75(4), 512-522.
[3] Petříček, Václav, Dušek, Michal and Palatinus, Lukáš. Zeitschrift für Kristallographie - Crystalline Materials, vol. 229, no. 5, 2014, pp. 345-352.