Performance of an electromagnetic liquid krypton calorimeter based on a ribbon electrode tower structure

Abstract The NA48 collaboration is preparing a new experiment at CERN aiming to study CP violation in the K 0 - K 0 system with an accuracy of 2 × 10 −4 in the parameter R e(ϵ′/ϵ). Decays in two π 0 's will be recorded by a quasi-homogeneous liquid krypton calorimeter. A liquid krypton calorimeter has been chosen to combine good energy, position and time resolution with precise charge calibration and long-term stability. The prototype calorimeter incorporating the final design of the electrode read-out structure is presented in this paper. An energy resolution of ≃3.5% √E with a constant term smaller than 0.5% has been obtained. The time resolution was found to be better than 300 ps above 15 GeV.