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Abstract

The Mu3e experiment aims to search for the highly suppressed charged Lepton Flavor Violation (cLFV) decay process μ+ -> e+e+e- with a sensitivity of 10-16, which is four orders of magnitude better than the current exclusion limit. The Tile Detector, composed of scintillation tiles and Silicon Photomultipliers (SiPMs), is designed to provide the most accurate timing measurement with a resolution of <100 ps and an efficiency close to 100%, playing a crucial role in accidental background suppression. This thesis covers the study of the radiation damage impacts on the Tile Detector, focusing primarily on the most radiation-damage-sensitive component, the SiPM. The radiation environment in the Mu3e experiment has been estimated using a GEANT4 simulation, and a radiation damage test of the Tile Detector Matrices has been conducted at the same beamline as the actual Mu3e experiment, reaching 70% of the maximum dose. A comprehensive laboratory characterization has been carried out to assess the impact on the SiPMs, particularly the noise of radiated SiPMs. The performance characterization in the beam-test campaign reveals that a timing resolution better than 60ps and efficiency close to 100% can be achieved with suitable signal readout electronics. Based on the radiation study results, modifications have been suggested for the current Tile Detector support system and readout electronics to maintain optimal performance in the presence of radiation damage.