Physics sources of noise in ring imaging Cherenkov detectors

The combination of a simulation program for the detector response with a transport code like FLUKA allows the detailed study of physics sources of noise in the RICH. As an example we present the results of a full simulation of the RICH response in the ALICE radiation environment for the highest anticipated charged particle multiplicities of 8000 particles per unit of rapidity in central PbPb collisions at s=5.5 TeV/nucleon. The contributions of primary and secondary charged and neutral particles to the overall occupancy are discussed.