Running experience with the ZEUS calorimeter

The ZEUS calorimeter has now been operated for almost two years, collecting ep collision data at HERA. This uranium-scintillator calorimeter covers 99.8% of the solid angle and has an energy resolution of 35%/√E for hadrons and 17.5%/√E for electrons. It is intercalibrated at the level of 1% with the natural uranium radioactivity. It achieves better than 1 ns timing resolution for energy deposits greater than 4.5 GeV. It has an excellent noise performance with no coherent noise and a dynamic range equivalent to 16 bit. With the readout of its ~12000 channels, operated in pipelined fashion running at 10 MHZ for 5 μs, and the trigger, it is a major piece of hardware which has to be kept operational and well calibrated. We review the detector as well as its readout and discuss the methods used for calibration and monitoring. The stability, the energy as well as the time calibration will be covered