LHC and the ATLAS Detector

Abstract

The Large Hadron Collider (LHC) [1] is a two-ring superconducting hadron accelerator and collider located at the European Organization for Nuclear Research (CERN) center at the French-Switzerland border. The LHC is installed in the 27 km tunnel constructed for the Large Electron Positron Collider (LEP) experiment  [2] which lies between 45 and 170 m below ground. In 1996, the construction of a 14 TeV LHC was approved  [3]. The LEP experiment ran from 1989 to 2000 when it was closed to liberate the tunnel for the LHC. While the LEP experiment collided electrons and positrons, the LHC primarily collides bunches of protons at four interaction points around the ring where four independent experiments are located: ATLAS  [4], CMS  [5], LHCb  [6], and ALICE  [7]. ATLAS and CMS are general purpose detectors aiming to run at high luminosities, with peak luminosity of $L = 2\times 10^{34} \text { cm}^{-2}\text { s}^{-1}$. LHCb is designed to study b-hadrons with peak luminosity of $L = 2\times 10^{32} \text { cm}^{-2}\text { s}^{-1}$ and ALICE is designed to study heavy ion collisions with peak luminosity of $L = 2\times 10^{27} \text { cm}^{-2}\text { s}^{-1}$. The LHC complex and the four experiments are shown in Fig. 3.1.