Data analysis from the beam test at DESY for the FoCal prototype

Abstract

FoCal, which stands for Forward Calorimeter, is a project to which the Subatomic Physics Institute of the Utrecht University contributes. The goal of FoCal project is the construction and development of a new high resolution electromagnetic calorimeter. This calorimeter will measure electromagnetic showers and tracks in the forward direction at the ALICE experiment at CERN, Switzerland. In this thesis, data taken from a beam test by the constructed FoCal prototype at DESY, Germany on March 2012 are analyzed. Beams of pure electrons at 2 and 5 GeV were used. Two steps are followed in this analysis, for both different energy data sets: The first is the investigation of the longitudinal shower profiles in order to study the behavior of the detector and calculate its energy resolution. Multiple methods are followed for detector calibration to improve the energy resolution. The second is the investigation of the lateral shower profiles which leads us in the calculation of the Moliere radius. Lateral profiles also help us to investigate the alignment of the prototype. In addition, some preliminary work with the scintillator trigger system and chip testing is also shown. All the results from the analysis are compared to the values calculated from the simulations and theory. The results from the analysis of the longitudinal and lateral profiles of the first testing of the FoCal prototype show that FoCal prototype behaves well as an electromagnetic calorimeter but the energy resolution that it shows is still away from what it was expected. Of course, modifications, changes and improvements can be made and the goals of the project could be probably reached.