on CMS information server CMS NOTE 1998 / 092 The Compact Muon Solenoid Experiment

We have measured the response of a CMS prototype silicon detector to pions and protons with momenta of 270 to 405 MeV/ c. Many of these low momentum particles will be produced in the proton-proton collisions at the LHC and due to the strong magnetic field in the CMS tracker volume the particles will traverse the detector planes at very different angles. To study the detector response under these conditions we have varied the incidence angle in a testbeam from 0 t 70 . The data were analysed in terms of the signal, the signal-to-noise (S/N) ratio and the number of strips in a cluster. In addition a simulation is shown, which extrapolates the testbeam data, obtained using low noise electronics, to a scenario with lower S/N ratio. The latter is expected to represent the conditions in the LHC experiments, due to radiation damage and the use of fast readout electronics.