Current and future challenges when operating the ATLAS Liquid Argon Calorimeter

The Liquid Argon Calorimeters are employed by ATLAS for precision electromagnetic calorimetry and for hadronic and forward calorimetry in the forward region. They also provide inputs to the first level of the ATLAS trigger system. Since 2022, the LHC has restarted with the perspective of an increase of the instantaneous luminosity and pile-up of up to 80 interactions per bunch crossing. The HL-LHC upgrade planned to be fully functional in 2029 should push the pile-up even further. To cope with these always harsher conditions the readout of the LAr Calorimeters had to be updated. In the LHC shutdown before 2022 a new trigger readout path has been installed that improved significantly the triggering performances on electromagnetic objects. This was achieved by increasing the granularity of the readout units available per collision by a factor of up to 10. New digitizer and processing boards were added on and off detector taking advantage of the recent electronics. This allowed a very compact and very efficient system treating up to 31Tbps. With the expected HL-LHC pile-up of 200 proton collision every 25ns and the induced increase of radiation dose, the current readout will have to be fully exchanged. The most recent and powerful technology allowing now to readout the full detector granularity at 40MHz will push the amount of data that could be processed online even further to always improve the efficiency of the event selection. This contribution will highlight the present and futures the challenges in the operation of such a detector.