Crosstalk, cathode structure and electrical parameters of the MWPCs for the LHCb muon system

This note discusses the electrical characteristics of the Multi Wire Proportional Chambers (MWPCs) for the LHCb muon system that were originally developed at PNPI. Optimized layouts for cathode structure and readout traces together with the expected crosstalk numbers are presented. We conclude that cathode pad dimensions should not be smaller than 3 cm in order to limit the cluster size to smaller than 1.2. We also conclude that a front-end electronics input resistance of less than 50 Ohm is preferred in order to limit the capacitive crosstalk. In some regions a resistance of 100 Ohm might be acceptable. In order to limit the crosstalk for chambers with a 'chessboard' cathode structure it is essential that we run the signal traces parallel to the wires.