Development of new readout electronics for the ATLAS LAr calorimeter at the sLHC

The ATLAS Liquid Argon (LAr) calorimeter consists of 182,486 detector cells whose signals need to be read out, digitized and processed, in order to provide signal timing and the energy deposited in each detector element. The current readout electronics is not designed to sustain the ten times higher radiation levels expected at sLHC in the years beyond 2017, and will be replaced by new electronics with a completely different readout scheme. The future on-detector electronics is planned to send out all data continuously at each bunch crossing, as opposed to the current system which only transfers data at a trigger-accept signal. Multiple high-speed and radiation-resistant optical links will transmit 100 Gbps per front-end board, each covering 128 readout channels. The off-detector processing units will not only process the data in real-time and provide digital data buffering, but will also implement trigger algorithms. An overview about the various components necessary to develop such a complex system will be given. The current R&D activities and architectural studies of the LAr Calorimeter group will be presented, in particular the on-going design of the mixed-signal and radiation hard front-end ASICs, the Silicon-on-Saphire (SOS) based optical-link, the high-speed off-detector FPGA based processing units and the power supply distribution scheme.