Study of Prompt Dimuon and Charm Production with Proton and Heavy Ion Beams at the CERN SPS

The NA60 detector complements the muon spectrometer and zero degree calorimeter previously used in NA50 with new state-of-the-art silicon detectors, placed in the target region. A radiation hard beam tracker, made of silicon microstrip detectors operated at 130 K, is placed on the beam line, upstream of the target system. It gives the transverse coordinates of the interaction point on the targets with a precision around 20 micron, allowing us to measure the offset of the muon tracks, and tag events where a pair of D mesons was produced. Downstream of the target system, and inside a dipole magnetic field of 2.5 T, we have a silicon tracking telescope, that tracks the charged particles and allows us to identify which one of them provides the best match to the muon measured in the muon spectrometer, placed behind a 5.5m silicon microstrip planes complemented by pixel planes. For the ion runs, the very high multiplicity of charged particles imposes the exclusive use of radiation tolerant pixel detectors.