• beam measurements
• accelerator physics

The MEG-II experiment is a particle physics experiment designed to search for the rare decay of a muon to an electron and a photon, aiming to explore new physics beyond the Standard Model, via Charged Lepton Flavour Violation (cLFV). A precise understanding of the beam optics is crucial for optimizing the experiment’s sensitivity and ensuring its success. During my master’s thesis I performed the measurements for the beam tuning for the last part of the physics run 2022 and for the physics run 2023. That was a chance to directly put my hands on the beam line elements of the MEG-II πE5 beam line and become acquainted with the beamline elements themselves. In this study I implemented for the first time the MAD-X simulation tool to describe the πE5 beam line. To achieve this, I first developed a comprehensive model of the MEG-II beamline using MAD-X, an open-source beam optics simulation software for designing and simulating particle accelerators. The model includes all relevant magnetic and electrostatic elements, as well as a detailed description of the beam and its initial conditions. The simulation results were initially compared to the G4Beamline’s, a Geant4-based toolkit specifically tailored for beamline simulations, and the model was refined until a satisfactory agreement was reached. The comparison between MAD-X and G4Beamline results provided valuable insights into the differences and limitations of both tools, as well as the level of agreement that can be expected in the context of the MEG-II experiment. To further validate the MAD-X model and assess its accuracy, a benchmark study has been performed with experimental data during beam-time in preparation of physics run 2023 of MEG-II experiment, when beam studies have been carried out at the collimator system as well as at the center of the experiment with different diagnostic tools. The motivation for this work arises from the need to accurately model the MEG-II beam line, particularly in terms of beam optics and particle trajectories.
The primary objective is to provide a detailed and reliable simulation framework that can be used by beamline users to study and optimize various aspects of the experiment, such as beam transport, energy deposition, and background reduction. The outcome of this thesis is a robust and well-validated beam optics simulation for the MEG-II experiment that can be employed by beamline users for various purposes, from the optimization of experimental configurations to the development of new analysis techniques. The comparison between MAD-X and G4Beamline results further establishes the reliability of the developed model and provides a valuable benchmark for future studies.