Fast electronic readout of microstrip gas chambers

Abstract

The Microstrip Gas Chamber (MSGC) is a major element in the tracking system of the Compact Muon Solenoid (CMS) detector for use at the forthcoming Large Hadron Collider (LHC), to be built at CERN. The MSGC for this application will have the gas gap reduced to a few millimetres, leading to short charge collection times in line with LHC requirements. Nevertheless, the charge produced by the passage of a particle through an MSGC is irregularly distributed over a period of approximately 60 ns; thus the front end signal processing requires careful optimisation to ensure that the combination of detector and electronics meets the required criteria for speed and charge collection efficiency. Since the signals are of similar magnitude, modifications of amplifiers used for reading out silicon microstrip detectors are well suited to MSGC use. An attractive possibility is to employ a variation of the deconvolution method in which a weighted sum of three consecutive samples of the amplifier output is used to extract the magnitude and timing of the detector current pulse. Simulated MSGC current pulse shapes are used to evaluate the feasibility of using the deconvolution method for the MSGC readout chain.