Introduction to the ATLAS detector at the LHC

ATLAS(A Toroidal LHC ApparatuS) is one particle detector at the large hadron collide (LHC), which is the world's largest and most powerful particle accelerator at the EUropean Organization For Nuclear Research(CERN) in Switzerland. ATLAS is intended to be a general-purpose detector, rather than focusing on a particular physical process. The most famous result on ATLAS is that it (together with CMS, another detector at LHC) reported the evidence for the existence of a particle consistent with the Higgs boson. The paper is a survey of the component and mechanism of the ATLAS detector. The ATLAS detector consists of three major parts: the Inner Detector, the Calorimeter, the Muon Spectrometer. The Inner Detector consists of the pixel detector, the semi-conductor tracker (SCT) and the transition radiation tracker(TRT). The calorimeter consists of electromagnetic calorimeter and the hadron calorimeter. The muon spectrometer is an extremely large tracking system which consists of two major parts: 1) precision-tracking chambers, 2) triggering-tracking chambers.