Parametrization of the Response of the Muon Barrel Drift Tubes

This note describes the parametrization of the response of the drift cells of the CMS barrel muon chambers based on the final design of the cell. The details of the simulation of the cell with the GARFIELD program are presented, together with comparisons with test beam data. The results, expressed in terms of the time-to-drift-distance relation of the cell for different configurations of the magnetic field and for different incidence angle of particles, are contained in a set of digitization functions which have become part of the official simulation and reconstruction software of CMS. This function supersedes previous results based on earlier designs of the drift tubes.