Development of the ATLAS Liquid Argon Calorimeter Readout Electronics for the HL-LHC

A new era of hadron collisions will start around 2027 with the High-Luminosity LHC, that will allow to collect ten times more data that what has been collected since 10 years at LHC. Five times higher instantaneous luminosity i.e. 8 billion collisions per second will happen. In order to withstand with the new specifications, the ATLAS Liquid Argon Calorimeter readout electronics will be upgraded during the 2025-2027 shutdown. Four subsets of the whole readout chain are concerned and are described here. Two of them are front-end electronics dedicated to the precise sensing of the detector cells, the digitization, the serialization and the optical transfer of the data to the off-detector electronics. The front-end electronics has to be tolerant to radiation up to 140 krad. The first subset is the new front-end board. It will amplify, shape and digitize on two gains the ionization calorimeter signal. Multiple silicon circuits have been designed for this purpose. The second is the new calibration board which will allow the precise calibration of all 182 500 channels of the calorimeter by injecting well known amplitude and shape pulses. The off-detector electronics is also made of two subsets. One is taking care in distributing the timing, trigger and control interface to the on-detector electronics. The other handles to process the huge data bandwidth coming from the 1524 front-end boards ie. 31912 optical fiber at 10.24 Gbps ~ 320 Tbps to compute signal energy, time-stamping and send the data to the online processing system.