Test results of a full size prototype of the muon chambers for region M2/R4 of the LHCb muon system

A full size prototype M2R4-01 of the Wire Pad Chambers for region M2/R4 of the LHCb Muon System hs been constructed at PNPI and tested in the T11 beam at CERN. The prototype contained two double-gap chambers with the sensitive area of 25x120 cm2. Each double-gap chamber contained 24 wire pads of 5x25 cm2 size. The prototype was fully instrumented with the FE electronics based on SONY chips with active adapters at the input allowing to optimize the parameters of the read out channels. The chamber was tested with four different concentrations of the gas components in the Ar/CO2/CF4 gas mixture. The beam tests showed quite satisfactory performance of the M2R4-01 prototype : a wide efficiency plateau uniform over the whole sensitive area of the chamber, low noise rates and cross-talks. It was demonstrated that the gas mixtures Ar(40%)+CO2(40%,30%)+CF4(20%,30%) provide higher stability against the HV-trips thus extending essentially the operational plateau of the chamber

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

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

Wire pad chambers and cathode pad chambers for the LHCb muon system

A proposal for Wire-Pad-Chambers and Cathode-Pad-Chambers for the LHCb Muon system is presented. It is shown that a single technology satisfies the requirements of almost the entire detector, garanteeing maximum uniformity. The muon system layout based on this technology is shown, and the chamber geometry specifications together with electronics considerations are discussed. An overview of prototype results are presented, followed by considerations on ageing. Finally construction and cost issues are outlined