The NA48 liquid krypton calorimeter description and performances

The NA48 experiment at CERN aims at making a precision study of direct CP violation in neutral kaons, by measuring Re(ε´/ε) with an accuracy better than 0.02%. To achieve this goal, the experiment requires a neutral detector with fast response, high efficiency in a high-rate environment (~MHz), long-term stability, sub-nanosecond time resolution, millimetric space precision, and an excellent energy resolution (1%) in the 5→100 GeV range. To achieve these performances, a quasi-homogeneous Liquid Krypton calorimeter has been chosen, designed with a projective tower geometry, high transversal segmentation, and fast digital readout. The calorimeter was operative during the ´97 data taking period, its performances were thoroughly studied, and found to be in agreement with design requirements. A detector description and performances analysis are here presented