Polarimeter Receiver Prototyping and Testing for the South Pole Telescope Upgrade

Experimental evidence has so far been supportive for the inflationary Big Bang model of cosmology, while imposing other mysteries, such as the fact that dark matter and dark energy actually consist of 95% of the observable universe. The forthcoming upgrade of the South Pole Telescope, planned for 2010, will include a polarimeter with increased sensitivity. Measurements of the CMB polarization anisotropy to a high accuracy will describe the angular power spectrum of the B-mode polarization, which will help unravel some of the mysteries. We prototype and test a digital frequency multiplexed readout system for the SPT upgrade. The digital system has the advantage of being able to reconstruct the phase of the signals. We characterize the performance of the readout and we compare it to the theoretical expectations. The noise is found to be statistically insignificant (insert quantitative proof), and the system performs as expected, significantly better than the previous implementation. We conclude that the digital fMux readout system should be sent to the South Pole Telescope.