Développement et caractérisation de l'ASIC de lecture du calorimètre à haute granularité de l'expérience CMS pour le HL-LHC.

This thesis deals with the work carried out, is part of the latest update of the endcap calorimeters of the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC), which is now becoming the High Luminosity LHC (HL-LHC). This detector is the first 5D imager calorimeter in particle physics with over 6 million readout channels, operating in an intense hadronic environment, with over 8 billion collisions per second. These constraints imposed by the environment, the complexity of its geometry, and the desired physical performance necessitate the development of a state-of-the-art readout ASIC for this ultra-granular calorimeter (HGCal). Therefore, this thesis addresses the impact of a highly radiative environment of a p-p collider on 130nm CMOS technology, as well as the hardening methods against cumulative dose effects (TID) and single event effects (SEE). The final part will focus on analysis of data collected during irradiation campaigns with heavy ions, X-rays, and finally protons, to validate the hardening methodology used.