Abstract:
AMBER is a new experiment at CERN's SPS studying fundamental questions of hadron physics using high-energy muon, pion, kaon and proton beams. It successfully concluded its first physics beam time in 2023, yielding valuable input for dark matter searches by measuring the production cross section of antiprotons impinging on helium. This study will be extended in 2024. In 2025, a first measurement of the proton electric form factor is scheduled, using elastic muon-proton scattering. New large-size planar GEM detectors are essential for the tracking of particles with small scattering angles. While for the antiproton production measurements, the new detectors will be operated with triggered readout electronics (APV25), the measurement of the proton form factor requires the application of a self-triggering chip (VMM3a). Extensive tests were performed on the noise performance with both readout variants. A full prototype detector read out by 48 VMM3a chips was tested in a pilot run in 2023. Also other new features of the new detectors are being studied. This presentation aims to provide a comprehensive overview of AMBER's new GEM detectors.