Comparative study on charging-up of single, double and triple Gas Electron Multipliers (GEM)

In this paper, a detailed investigation has been carried out to understand the physics behind GEM charging-up and its effects on gain. Experiments have been performed on both double and triple GEM with the help of Fe-55 X-ray source and a comparative study of these configurations along with the single GEM results observed in our previous work has been reported. The increase in gain due to polarization of GEM foil dielectric and reduction in gain due to charge accumulation on dielectric are studied for various field configurations and different radiation intensities.