Performance Simulation of Cathode Strip Chamber Protype P1.

The results of simulation of the P1 prototype performance are presented. The P1 prototype is a full scale six-layers trapezoidal cathode strip chamber module designed for the CMS End Cap Muon System. The module was tested at Fermilab with cosmic rays. In this work, complete simulation from the initial ionization to the final amplitude and time distributions of the signals from the CSC as well as the reconstruction of the track coordinate was performed. The physical parameters of the electron behaviour in the gas mixture ( 27% Ar, 29% CF4, 44% CO2) are taken from the Biagi program with the Townsend coefficient and electrons attachment renormalized to fit the observed gas amplification factor and the spatial resolution dependence on a beam entrance angle. The simulation program has reproduced well the measured parameters of the P0' prototype including the time and spatial resolutions. This consideration showed also that 85% of the initial number of ionization electrons are lost due to attachment to gas mixture molecules before they reached the avalanche area. The results of modeling the P0' prototype performance were used for simulating the performance of the P1 prototype. The results are in a good agreement with the experiment.