The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 mu m to 243 mu m. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns.

Performance of the CMS cathode strip chambers with cosmic rays RID G-1804-2011 RID E-8846-2011 RID A-4009-2011 RID B-2993-2011 RID B-9140-2011 RID A-4578-2008

Bianchini L;MESSINEO, ALBERTO MARIA;TONELLI, GUIDO EMILIO;RIZZI, ANDREA;