Basics of numerical simulations of the signals from GEM detector

The Gas Electron Multiplier (GEM) is a detector used to register ionizing radiation, e.g., soft X-rays. The detector of this type, built and developed at the IPPLM institute, allows registering X-rays in the energy range of 2-20keV and determining its intensity in time, as well as its spatial position and energy. Simulating the work of such a detector, performed in parallel to experimental research, and sometimes preceding it, allows for optimization of construction and operation parameters of this detector with respect to the requirements set in the experiment, and allows for a better understanding of the physical processes occurring in the detector. The paper presents how simulations are performed, i.e. describes applied programs, main stages of simulation such as the construction of a three-dimensional model of the detector for calculations, the efficiency of X-ray detection, its conversion to primary electrons and the process of avalanche formation. Finally, the results obtained in this way are also presented.