Abstract:
The AMBER experiment is a new fixed-target experiment at CERN's M2-beamline which started data taking in 2023 and intends to answer fundamental questions in the field of hadron physics. One important experiment in phase-1 of AMBER is the measurement of the proton charge radius by muon-proton elastic scattering. GEM detectors will be used to reconstruct scattered-muon trajectories and momenta. The experimental setup requires a continuously streaming readout of all detectors. Current plans are to use a readout system based on the VMM3a ASIC as GEM frontend chip, featuring a continuous self-triggered data aquisition.
In September 2023, data were taken under realistic AMBER beam conditions using a prototype large-size triple-GEM detector with continuous VMM3a readout. In this contribution, we will present the ongoing data analysis aiming at finding a stable working point of the detector fulfilling the requirements of the experiment. This involves characterizing the detector in terms of efficiency, signal-to-noise ratio, position and time resolution.