The NA49 detector is a wide acceptance spectrometer for the study of hadron
production in p + p, p + A, and A + A collisions at the CERN SPS. The main
components are 4 large-volume TPCs for tracking and particle identificatio
n via dE/dx. TOF scintillator arrays complement particle identification Cal
orimeters for transverse energy determination and triggering, a detector fo
r centrality selection in p + A collisions, and beam definition detectors c
omplete the set-up. A description of all detector components is given with
emphasis on new technical realizations. Performance and operational experie
nce are discussed in particular with respect to the high track density envi
ronment of central Pb + Pb collisions. (C) 1999 Elsevier Science B.V. All r
ights reserved.