Characterization and Commissioning of the QUBIC instrument dedicated to the study of the Cosmic Microwave Background Polarization

The cosmic microwave background (CMB) is the only electromagnetic witness of the beginnings of the Universe present today. Thanks to this one, astrophysicists observe, interpret and collect information in order to understand one of the biggest mystery of our time: how was born our Universe? In many respects, the latter has already given us a lot of information about its 'simple' existence up to its temperature anisotropies allowing us to probe even more the beginnings of our Universe. The new challenge of cosmology today is to precisely characterize the polarization of the CMB. Although we have already detected the E-modes coming form density fluctuations, the B-modes created by primordial gravitational waves are still a source of questioning by their expected weak signals. It is in this context that the QUBIC (Q and U Bolometric Interferometer for Cosmology) collaboration was born. This telescope dedicated to the study of the CMB polarization, is a novelty in the field because it combines low systematic effects of interferometry with the sensitivity of bolometers cooled to very low temperatures. The Technological Demonstrator (TD) aims to show the feasibility of combining interferometry and bolometric detection. The electronic readout system is based on an array of 128 NbSi transition edge detectors (TES) cooled to 350 mK and readout by 128 SQUIDs at 1 K controlled and amplified by an ASIC at 40 K. This readout design creates 128:1 time-domain multiplexing. The technical demonstrator underwent a laboratory test campaign at APC and then was sent to Salta, Argentina for a second test campaign before being deployed at its observation site. Evaluation of the QUBIC bolometers and readout electronics includes measurement of the I-V curves, time constant and noise equivalent power. Today this sensitivity is about 2.10^-16 W/√(Hz). This thesis reports on the work I did during the integration and optimization of the readout chain as well as the shipping of the telescope to Argentina and its integration on site. (author)