FASER’s Electromagnetic Calorimeter Test Beam Studies

FASER, or the Forward Search Experiment, is a new experiment at CERN designed to complement LHC’s ongoing physics program, extending its discovery potential light and weakly interacting particles that may be produced copiously LHC in far-forward region. New targeted by such as long-lived dark photons axion-like particles, are characterised signature with two oppositely charged tracks multi-TeV range emanate from common vertex inside detector. The full detector was successfully installed March 2021 an side tunnel 480 m downstream interaction point ATLAS FASER planned operational for Run 3. composed of silicon-strip tracking-based spectrometer using three dipole magnets 20 cm aperture, supplemented four scintillator stations electromagnetic calorimeter. calorimeter constructed spare LHCb modules. modules Shashlik type interleaved lead plates result 25 radiation lengths 1% energy resolution TeV showers. In 2021, test beam campaign carried out one SPS lines set up calibration system preparation data taking. relative response electrons energies between 10 300 GeV, well high muons pions, has been measured under various voltage settings positions. resolution, calibration, particle identification capabilities presented.