Searching for Primordial Gravitational Waves at Degree Scales from the South Pole

We report on the preliminary performance of the BICEP2 mm-wave polarimeter, deployed in 2009 to the South Pole and will observe through 2012. BICEP2 is currently imaging the polarization of the cosmic microwave background at 150 GHz using an array of 512 antenna-coupled superconducting bolometers. It has been designed for high sensitivity and low systematics in order to pursue the primordial B-mode polarization signal. The instrument and its characterization are presented in this thesis, with particular attention to the detectors and readout system. The instrument sensitivity, mapping speed are discussed along with the expected constraint on the scalar-to-tensor ratio that should be made from one year of data.