Prototype Hardware Design and Testing of the Global Common Module (GCM) for the Global Trigger subsystem of the ATLAS Phase-II Upgrade

The HL-LHC will start operations in 2027, to deliver more than ten times the integrated luminosity of the LHC Runs 1-3 combined. Meeting these requirements poses significant challenges to the hardware design of the Trigger and Data Acquisition system. Global Trigger is a new subsystem, which will perform offline-like algorithms on full-granularity calorimeter data. The hardware implementation of the Global Trigger consists of three primary components: Multiplexer Processor layer, Global Event Processing layer, and demultiplexing Global-to-CTP Interface, all of which have identical hardware. The single Global Common Module hardware is implemented across the Global Trigger system.