Beam tests of WPC-7 prototype of iwire pad chambers for the LHCb muon system

Abstract

A new prototype of the Wire Pad Chamber for the LHCb Muon System, WPC-7, has been constructed at PNPI and tested in the T11 beam at CERN. This prototype proved to be more stable against the electrical discharges at high voltages thus extending the operational plateau of the chamber by 200V. This made it possible to operate with larger wire pad sizes up to 12x16cm2. This report presents the results from the beam tests of the WPC-7 prototype : time resolution and efficiency, cross-talk, noise counting rates, streamer probability measured at various high voltages and discriminator thresholds