Numerical Investigation on Electron and Ion Transmission of GEM-based Detectors Purba Bhattacharya, Sumanya Sekhar Sahoo, Saikat Biswas, Bedangadas Mohanty, Nayana Majumdar and Supratik Mukhopadhyay EPJ Web Conf., 174 (2018) 06001 Published online: 21 February 2018 DOI: 10.1051/epjconf/201817406001