Development of RE1/1 RPCs for the CMS muon trigger system

Abstract The first six Resistive Plate Chambers (RPCs) of RE1/1 in the forward region of the Compact Muon Solenoid (CMS) detector were constructed and are being tested. These RPCs cover the pseudo-rapidity region from 1.6 to 2.1 and will serve as the base detector for the CMS RPC muon trigger. We report that these six RPCs are being tested with the CMS RPC quality certification procedures and that a full measurement of a chamber efficiency of 95 ± 4 % has been achieved at an operating voltage of 9.4 kV. This performance demonstrates that the RPC is qualified to be tested at the closest distance to the beam pipe as the muon trigger detector at the full LHC design luminosity.