Upgrade plans for the ATLAS calorimeters

The ATLAS calorimeter is composed of detectors based on different techniques to exploit the best performance while maintaining a sufficient radiation resistance. A radiation resistant liquid argon (LAr) sampling calorimeter is used for all electromagnetic sections, for the endcap (HEC) and forward (FCal) hadronic sections. The most central hadronic section is, instead, a steel–scintillator sampling calorimeter (TileCal). Plans are already being developed for operation of the LHC and the detectors at an increased instantaneous luminosity about 5 times the original design value. There are plans for a two-phase detector upgrade. For Phase I, the LAr calorimeter trigger will be upgraded. For Phase II, the TileCal upgrade consists in replacing the on- and off-detector electronics and for the LAr system includes changes to the DAQ, the HEC cold electronics and the FCal. Development work for these options includes high rate tests of small test modules of the endcap and forward detectors.