CERN summer student program rapport: A better understanding of gas gain simulations in GEM detectors

The Gaseous Electron Multiplier (GEM) is used for the detection in the detection of ionizing radiation in high-energy physics experiments due to there high gas gain. This CERN summer project aimed to have a better understanding of the discrepancy between theoretically and experimentally obtained effective gas gains of this detector, which is currently a factor of. Our results do not lead to a conclusive cause of this inconsistency but show a significant shift in gas gain due to alterations in the geometry of a GEM hole. In adition, the surface potential of the polyimide in the presence of a surface current has been calculated, the effect of secondary electron emission has shown to be negligible and the electron transport algorithm of Garfield++ has been expanded.