Operation of a RPC with low resistivity bakelite for the endcap region of CMS in a high-rate environment

W e present the learn-test results for a real-size prototype resistive plate chamber (RPC) for the endcap region of the Compact Muon Solenoid (CMS) experiment at CERN Large Hadron Collides (LHC). The chamber built with relatively low resistivity bakelite was tested at the Gamma Irradiation Facility (GIF) at CERN under a high photon-flux environment with an effective cluster rate up to clout 1.2 kHz/cm(2). The characteristics of the present chamber are compatible with the previous results for the muon detection efficiency, time resolustion, mean travel time., and rate capability, which were obtained using a higher resistivity Bakelite. The present beam-test results ensure that the RPC made of relatively low resistivity bakelite is also suitable for the CMS muon trigger detector. In addition, we study the position resolution of the endcap RPC of the CMS. By using the median position of the cluster strips, the position resolution can be reduced to only half of the strip width.