ATLAS detector. Engineers working on part of the ATLAS (a torodial LHC apparatus) detector in a clean room at CERN (the European particle physics laboratory) near Geneva, Switzerland. The detector will be placed around the large hadron collider (LHC), CERN's highest energy particle accelerator. ATLAS is a general-purpose detector designed to measure the broadest possible range of particles and physical processes that could result from the collision of the proton beams within the LHC. A pilot run of the LHC is scheduled for summer 2007.