Fast simulation of the CMS detector at the LHC

A fast Monte Carlo Simulation of the CMS detector has been developed which is between 100–1000 times faster than its Geant4-based counterpart, at a similar level of accuracy. The methods applied in the fast simulation, both software and physics wise, are being outlined in this paper. This includes the concepts of simulating the interaction of particles with the detector material and the response of the various parts of the detector, namely the silicon tracker, the electromagnetic and hadron-calorimeters and the muon system.