The CHORUS scintillating fiber tracker and its monitoring systems

The scintillating fiber tracker system of the WA95/CHORUS experiment at CERN is briefly described. Its performances were monitored using high-energy muons associated to the neutrino beam. After three years of data taking, the system has shown to perform according to the design and to be robust, with a negligible fiber ageing. The different monitoring and calibration systems necessary to ensure high-resolution tracking are presented.