LKr calorimetry for the CP violation experiment NA48: recent test beam results

The NA48 collaboration is preparing a new experiment at CERN aiming to measure ϵ′ϵ in the K0-K0 system to the level of 2 × 10−4. The heart of the detector will be the electromagnetic calorimeter needed to reconstruct the neutral kaon decays. The choice of a liquid krypton calorimeter has been dictated by the need to combine excellent energy, position and time resolution with the possibility of a precise charge calibration and long term stability. Results obtained by means of a prototype calorimeter incorporating the final design of the electrode readout structure are presented.