Z-chamber and the trigger of the CMD-2 detector

Abstract A double layer cylindrical MWPC ( Z -chamber) is part of the CMD-2 detector. It serves both for precise measurements of track coordinates along the beam axis and for the first level trigger. The construction and performance of the Z -chamber are described. A fast gas mixture of 90% CF 4 + 10% i-C 4 H 10 was used to obtain a better time resolution. The measured time spread of the anode signals is σ = 4.1 ns. The first level trigger and a tracking processor are also discussed.