English: Paweł Możejko, PhD, DSc is explaining functional principle of the electrostatic electron spectrometer, used in Electronic Collisions Physics Laboratory at the Department of Atomic, Molecular and Optical Physics at Gdańsk University of Technology. Absolute total cross sections for electron scattering on molecular targets measured and computed in the laboratory were used, among others, for calibration of the Rosetta Space Probe's (launched by ESA spectrometers and for data normalization. The instrument shown in the photo is intended to be a part of a apparatus for research on interactions between low energy electrons and condensed matter.