The Phase-2 Electronics Upgrade of the ATLAS Liquid Argon Calorimeter System

The LHC high-luminosity upgrade in 2024-2026 requires the associated detectors to operate at luminosities about 5-7 times larger than assumed in their original design. The pile- up is expected to increase to up to 200 events per proton bunch-crossing. The current readout of the ATLAS liquid argon calorimeters does not provide sufficient buffering and bandwidth capabilities to accommodate the hardware triggers requirements imposed by these harsh conditions. Furthermore, the expected total radiation doses are beyond the qualification range of the current front-end electronics. For these reasons an almost complete replacement of the front-end and back- end readout system is foreseen for the 182,468 readout channels. The new readout system will be based on a free-running architecture, where calorimeter signals are amplified, shaped and digitized by on-detector electronics, then sent at 40 MHz to the back-end for further processing. Results from the design studies on the performance of the components of the readout system are presented, as well as the results of the tests of the first prototypes.