CMS Resistive Plate Chamber overview, from the present system to the upgrade phase I

Abstract

Resistive Plate Chambers have been chosen as dedicated trigger muon detector for the Compact Muon Solenoid experiment [1] at the Large Hadron Collider [2] at CERN. The system consists of about 3000 m(2) of double gap RPC chambers placed in both the barrel and endcap muon regions. About 5.6 fb(-1) (2010-2011) of proton-proton collision data have been used to study the performance of the RPC detector and trigger. A full high voltage scan of all the RPC chambers has been done at beginning of 2011 data taking to evaluate the working point chamber by chamber and to eventually spot aging effects. The excellent behaviour of the RPC detector can be summarized with an average detector efficiency of about 97%, an average cluster size of 1.8 and an intrinsic noise rate of 0.1 Hz/cm(2). This is a clear fulfilment of all the requirements decided 18 years ago in the CMS TDR document [3].