Prototype tests for the liquid Krypton, Calorimeter of the CP-violation Experiment NA48

This work 1s the result of a one year stay as a technical student in the NA48 group at the European Center for Nuclear Research CERN from May 1992 to May 1993. The NA48 experiment is a fixed target experiment at the CERN Super Proton Synchrotron (SPS) to study direct CP violation in neutral kaon decays. The aim of the experiment is the measurement of the ratio of the CP violation parameters £ '/£. Chapter 1 will explain the origin of these parameters and our current knowledge of their size. Chapter 2 will give a description of the NA48 experiment. A crucial part of the experiment will be a photon calorimeter filled with liquid krypton. It has to meet very ambitious demands concerning the high rate capability and the energy, space and time resolutions. In chapter 3 the principles of electromagnetic calorimetry and ionization chambers are reviewed. In 1992 two test beam exposures of a prototype of the liquid krypton calorimeter were performed. A description of these tests will be given in chapter 4. During the two tests I was engaged in the setup and operation of the trigger counters and the flash analog to digital converter (FADC) system. During the datataking phase I was involved in the actual data-taking. After the runs I participated in the analysis of the test beam results. This work consisted of programming parts of the official off-line code for the test beam analysis and of the study of particular aspects of the prototype tests. I analyzed the data from the FADC system and produced results for the energy, space and time resolutions. I also performed an investigation of nonuniformity effects in the calorimeter response. The results of my analysis are described in chapter 5, followed by a compressed summary in chapter 6.