The recent success of temperature and polarisation anisotropy measurements of the Cosmic Microwave Background, in particular by the satellites WMAP and Planck, have dramatically change the perspectives in modern Cosmology. They have confirmed the Hot Big Bang scenario and have contributed to establish a standard model of Cosmology called λCDM. Research are today focused on the measurement of a specific polarisation decomposition of the CMB signal : the B mode. These polarisation patterns on the sky would have been imprinted by gravitational waves during a very early period of the Universe called the inflation. Detection of primordial B-mode requires to increase instrumental constraint over 3 to 5 order of magnitude. This thesis address this problem on the instrumental aspect and especially in terms of detectors charac- terization. The transition edge sensor (TES) technology has already been used in many CMB experiments like SPT, ACT or Bicep 2. In order to reach the sensitivity required a huge effort is made to improve many aspects of the detectors : integration of large number of detectors, noise performances, optical coupling. Most of the TES bolometers technologies are based on a bi-layers sensors with a superconducting proximity effect. (Al/Ti or Mo/Cu). We chose to develop TES sensors with a Niobium/Silicon alloy instead, hoping to reduce the excess noise and to tune the critical temperature as low as we want. I will present the first characterization of this kind of technology, I(V) curve, complex impedance and noise performance. The TES are readout with a SQUID Time Domain Multiplexing prototype using a cold ASIC with a SiGe technology. 1
Characterization of a detection chain using superconducting bolometers for polarization measurement of the Cosmic Microwave Background