Efficiency Analysis of MUSE GEMs

The MUon Scattering Experiment (MUSE) at the Paul Scherrer Institute (PSI) mainly aims to address the disagreement in the measured proton charge radius. The experiment uses a mixed beam of electrons and muons, both positively and negatively charged, allowing the extraction of the proton charge radius from electron-proton and muon-proton scattering under identical experimental conditions. To track incoming beam particles before scattering, MUSE uses four Gas Electron Multiplier (GEM) detectors. The efficiency of each GEM detector is quantified using tracks reconstructed by the other three GEMs. The analysis includes studies of the overall GEM efficiency, as well as efficiencies along the x and y axes, for different particle species and under various high voltage (HV), low voltage (LV), and other variable settings. Quantifying the GEM efficiencies is crucial for ensuring optimal performance of the detectors during data taking. This talk will provide an overview of the MUSE GEM telescope and present the latest results from the efficiency analysis.