Performance of the Gas Gain Monitoring system of the CMS RPC muon detector and effective working point fine tuning

Abstract

The Gas Gain Monitoring (GGM) system of the Resistive Plate Chamber (RPC) muon detector in the Compact Muon Solenoid (CMS) experiment provides fast and accurate determination of the stability in the working point conditions due to gas mixture changes in the closed loop recirculation system. In 2011 the GGM began to operate using a feedback algorithm to control the applied voltage, in order to keep the GGM response insensitive to environmental temperature and atmospheric pressure variations. Recent results are presented on the feedback method used and on alternative algorithms. © CERN 2012, published under the terms of the Creative Commons Attribution licence 3.0 by IOP Publishing Ltd and Sissa Medialab srl.