Measurement of the temperature and polarization anisotropies in the cosmic microwave background with QUaD.

• Main Author: Zemcov, Michael B.
• Format: Thesis
• Language: English
• Published: 2006
• Subjects: QB Astronomy; Austral; South Pole; South pole
• Online Access: https://orca.cardiff.ac.uk/id/eprint/54564/; https://orca.cardiff.ac.uk/id/eprint/54564/1/U584847.pdf

This thesis paper describes QUaD, a millimetric polarimeter designed to precisely measure the temperature and polarization anisotropics in the cosmic microwave background (CMB) radiation. QUaD was built and integrated between 2000 and 2004, and commissioned at the south pole in the austral summer of 2004/2005. First light was achieved in February 2005, and QUaD acquired a full austral winter of data during that year. Modifications to the instrument were performed in the austral summer of 2005/2006, and QUaD is currently taking a second season of data. A third season is planned. QUaD is composed of a cryogenically cooled receiver mounted on a Cassegrain telescope using a 2.6 m primary mirror. The detectors are polarization sensitive Neutron Transmutation Doped germanium bolometers which are coupled to the optics via single- moded corrugated feed horns. These detectors are split between two frequency bands, 100 and 150 GHz, and the optics allow angular resolutions of 6.0 and 4.0 arcminutes in these two bands. The performance of the instrument has been characterized using extensive laboratory data, a battery of tests performed during commissioning, and specially designed measurements during the observing season. QUaD uses constant elevation azimuth scans with 15 degree lengths, allowing reconstruction of all 6 CMB power spectra in the range 50 < £ < 2000. Customized software and analysis methods are required to transform data time series from the telescope to refined data products. QUaD data have provided the most accurate measurements of the £-mode CMB power spectrum to date, as well as measurements of T-mode power competitive with the best high angular resolution experiments. These measurements provide a wealth of information, and both confirm our model for the early Universe as well as constrain cosmological parameters. Furthermore, QUaD measures the formation of structure after recombination, and can constrain the physics of inflation.