Development of large area, ultra-thin MAPS for the ALICE experiment at the CERN LHC

The ALICE experiment, installed at the CERN Large Hadron Collider, studies the collisions of nuclei at the ultra-relativistic energies provided by the LHC. The aim is to study the physics of strongly interacting matter at the highest energy densities reached so far in the laboratory, where the quark-gluon plasma forms. In 2021 ALICE completed a significant upgrade of its detectors, and it is now looking forward to start the design phase of a completely new detector for the next decade. The ALICE experiment is planning to upgrade the innermost part of its Tracking System with a novel vertex detector consisting of curved wafer-scale, ultra-thin silicon sensors arranged in perfectly cylindrical layers, featuring an unprecedented low material budget of 0.05% X0 per layer, with the innermost layer positioned at only 18 mm radial distance from the interaction point. This new vertex detector, planned to be installed during the LHC LS3, will reduce the material budget, and improve the tracking precision and efficiency at low transverse momentum, leading to a significant advancement in the measurement of low momentum charmed hadrons and low-mass dielectrons in heavy-ion collisions. The thesis includes test, measurement and characterisation of the early sensor prototypes.