Study and development of new silicon technologies for the ALICE 3 Time-Of-Flight detector

In preparation for the future ALICE 3 experiment proposed to be installed at the LHC at CERN in 2036, an extensive R&D program is actively addressing the challenge of developing a 20-picosecond technology for the Time-Of-Flight (TOF) detector. Various silicon technologies are under investigation to achieve this goal. Among those, Low Gain Avalanche Detectors (LGADs) constitute a promising solution. In this thesis, comprehensive R&D efforts focused on state-of-the-art LGADs are presented. A wide range of LGADs, both single channel sensors and matrices, including different thickness, area, doping and inter-pad design have been fully characterized with laboratory measurements and studied first with a laser setup and subsequently using particle beams at CERN facilities. First tests of 25 μm and 35 μm LGADs compared to 50 μm-thick sensors highlighted the potential of a thinner design for improved time resolution. This prompted further investigations into progressively thinner sensors, arriving to test the first 15 \textmu m-thick LGADs ever produced by FBK. Additionally, the innovative double-LGAD concept was introduced to address the challenge of small input signals in the electronics. Notably, this new concept not only yields the significant benefit of an enhancement of the charge at the input of electronics which allows for reduced power consumption, but also translates into an improvement in overall time resolution. Finally, a dedicated study has been performed to determine the impact of particle incidence angles on the time resolution, a crucial aspect to be taken into account in the ALICE 3 experiment. Overall, this R&D campaign on LGAD detectors, finally resulted in sensors that meet the time resolution requirements of ALICE 3 Time-Of-Flight detector, establishing them also as strong candidates for future-generation experiments.