ATLAS LAr Calorimeter Commissioning for LHC Run 3

Abstract

The Liquid Argon (LAr) calorimeter detector in ATLAS is instrumental in measuring the energy deposits of particles traveling through the detector and for identifying electrons, photons, and jets. As Run 3 introduces higher luminosity, LAr must adapt to the increased radiation and pileup conditions to preserve acceptable trigger thresholds. During the second Long Shutdown, new boards were installed on- and off-detector as a part of the Phase-I upgrade, resulting in a ten fold granularity improvement and increased precision for data sent to the Level-1 Calorimeter (L1Calo) trigger. The Phase-I upgrade is compatible with the planned high-luminosity LHC (HL-LHC). We present an overview of the Phase-I upgrade for LAr and its performance for the start of Run 3.