CMS RPC Technical trigger performances in cosmic runs

Abstract

The Compact Muon Solenoid (CMS) is one of the four experiments at the CERN LHC collider. CMS consists of a full-solid-angle-coverage multi-purpose detector provided with a solenoidal magnet, a inner central tracking, calorimeters, and an outer muon-detecting system. The muon system consists of three different types of gaseous chamber detectors: Cathode Strip Chambers (CSC), Drift Tubes Chambers (DT) and Resistive Plate Chambers (RPC). These detectors are designed to provide both trigger and muon tracking capability: CSC’s in endcaps and DT’s in the barrel region and RPC’s in both regions. The commissioning phase of the RPC system started in Summer 2007. It exploited several tools for the chambers status monitoring, noise and chamber performance studies. Two technical triggers for the RPC system relying on cosmic muons detection have been used and validated. Several data-taking runs using all sub-detectors (Global runs) have been crucial in order to verify the expected RPC performances and reliability within the trigger system. A summary of the main results is reported, divided into two main areas: RPC chambers performance and RPC technical triggers performance.