oa The Gas Electron Multiplier For Charged Particle Detection

The Gas Electron Multiplier (GEM) has emerged as a promising tool for charged particle detection. It is being developed as a candidate detection system for muon particles for the future upgrade of Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC). It consists of a thin polymer foil, metal coated on each side and pierced by a high density of holes (see figure). The potential difference between the electrodes and the high electric field generated by the holes will further amplify the electrons released in the gas of the detector by the ionizing radiation or the charged particle crossing the detector. In this work, we will report on the results of the performance of the GEM prototype at the tests conducted at the CERN acceleration facilities using pion and muon beams. The main issues under study are efficiency, gain uniformity, and spatial resolution of the detector.