The ATLAS Experiment at the CERN Large Hadron Collider

Abstract

The Large Hadron Collider (LHC) at CERN will extend the frontiers of particle physics with its unprecedented high energy and luminosity. Inside the LHC, bunches of up to 1011 protons (p) will collide 40 million times per second to provide 14 TeV proton-proton collisions at a design luminosity of 1034 cm􀀀2s􀀀1. The LHC will also collide heavy ions (A), in particular lead nuclei, at 5.5 TeV per nucleon pair, at a design luminosity of 1027 cm􀀀2s􀀀1. The high interaction rates, radiation doses, particle multiplicities and energies, as well as the requirements for precision measurements have set new standards for the design of particle detectors. Two general purpose detectors, ATLAS (A Toroidal LHC ApparatuS) and CMS (Compact Muon Solenoid) have been built for probing p-p and A-A collisions. This paper presents a comprehensive overview of the ATLAS detector prior to the first LHC collisions, written as the installation of the ATLAS detector is nearing completion. This detector represents the work of a large collaboration of several thousand physicists, engineers, technicians, and students over a period of fifteen years of dedicated design, development, fabrication, and installation.