Operations and Performance of the CMS DT and RPC muon systems

Abstract

The muon spectrometer of the Compact Muon Solenoid (CMS) at the CERN Large Hadron Collider (LHC) is equipped with a redundant muon system based on Drift Tubes (DT) Chambers, Cathode Strip Chambers (CSC) and Resistive Plate Chambers (RPC) for muon identification, precise momentum measurement and triggering. On 30th March 2010, LHC started proton proton collisions at a center of mass energy of 7 TeV. The operations and performance of the DT and RPC systems during the first three years of LHC activity with increasing instantaneous luminosity will be reported. The DT local trigger performance is described, showing how the challenging design goals have been met. Special attention will be given to the RPC working point calibration procedure and to the efficiency stability of the RPC system, confirming the excellent behavior and the fulfillment of the CMS requirements. Finally the radiation background levels in the DT and RPC systems have been measured. Extrapolations to the LHC design conditions are also discussed.