Performance of the Barrel Ring Imaging Cherenkov counter of DELPHI

The Barrel Ring Imaging Cherenkov detector of the DELPHI experiment at LEP provides particle identification by the detection of the radiation emitted in UV transparent perfluorocarbons. We will present the principles of the operation of the detector together with a discussion of the automatized control of all the relevant physical parameters. The observed performances of the detector are very close to their design values. >