Study of the anode self-trigger ability of the ME1/1 CMS Endcap Cathode Strip Chamber

The influence of the high background rates on the Cathode Strip Chamber (CSC) anode trigger ability has been studied. The investigation has been made with a P3 prototype of the CSC of ME1/1 Endcap muon station of the CMS experiment (CERN). The work has been done at the Gamma Irradiation Facility (GIF, CERN). P3 has been installed at the SPS X5c muon beam line in a background field of 137 Cs source. The CSC timing resolution and the track registration efficiency as a function of gamma rate are presented.