Study of spatial and Angular Resolution of SPACAL Prototypes for the LHCb ECAL Upgrade II

The aim of this thesis is to investigate the performances of the SpaCal prototypes in terms of the angular and spatial resolution, which are strictly correlated to each other. A position ability around 1 mm for the ECAL would guarantee first an efficient separation of the overlapping showers, and secondly a precise reconstruction of the position for both neutral and charged particles. For the charged ones, the signals in ECAL are matched with the trajectories reconstructed from the tracking detector to perform an accurate particle identification. As for the neutral particles, the position measure- ment is only available from the calorimeter, and it is fundamental to reconstruct events. Also a good angular resolution is required for the Upgrade II of the ECAL to study theories with physics beyond the Standard Model that involve particles with a detectable decay length from the interaction point, known as Long-Lived Particles (LLP). To investigate their performance, the modules were tested both at SPS and at DESY facilities, and the results were compared with the outcome of detailed Monte Carlo simulations, where the test-beam setup used for the data acquisition was reproduced