Masking Problematic Channels in the Liquid Argon Calorimeter for the High-Level Trigger of ATLAS

Read-out channels in the liquid argon (LAr) calorimeter of the ATLAS detector are susceptible to various kinds of faults, which can impair the selection of events made by the trigger system. General-purpose software tools have been developed for dealing with problematic calorimeter channels. In order to give High-Level Trigger (HLT) algorithms robustness against detector problems, these tools have been applied in the HLT calorimeter data preparation code to mask problematic channels in the LAr calorimeter. Timing measurements and optimizations have been conducted to assess and minimize the impact of these operations on the execution speed of HLT algorithms. The efficacy of the bad-channel masking has been demonstrated using cosmic-ray data.