ATLAS LAr calorimeter degradation studies for HL-LHC

The future High Luminosity LHC upgrade (HL-LHC) will increase the luminosity by a factor of ten, which implies radiation hardness requirements for the LHC detectors. This requires to test the ATLAS Liquid Argon (LAr) calorimeters for higher intensities. In several test beam campaigns at IHEP/Protvino, the HiLum collaboration investigated small-size modules of the electromagnetic, hadronic, and forward calorimeters. The intensity of beam varied over a wide range (10⁶ to 10¹² p/s) and beyond the maximum expected at HL-LHC for these calorimeters. The correlation between beam intensity and the electromagnetic calorimeter HV current signal is used to quantify the possible signal degradation. The results of the detector performance before and after operation in highest beam intensities are presented.