Cosmic Foreground Explorer: A Balloon-Borne Study of the Cosmic Microwave Background

The Experimental Cosmology group at UCSB is currently pursuing balloon-borne observations of the cosmic microwave background radiation (CMBR). The CMBR is a focal point of modern cosmology and physics as it contains evidence for the origins of the universe, and the current composition of matter and antimatter. While there have been numerous missions mapping the spectrum and anisotropies in the CMB, there is only limited data on the polarization of the radiation. We believe this data has the potential to uncover gravitational waves in the early universe and is of particular interest in the study of cosmic inflation. To measure the polarization anisotropies, telescopes are required to be ultra-sensitive, have a high resolution, and operate cryogenically.  Our research currently focuses on our quarter-wave plate polarization rotator. The rotator allows for the cryogenic receivers to detect the polarization of incoming radiation. Since the receivers themselves are sensitive to only one polarization, the rotator allows the polarization of the incoming radiation to be rotated to match the detection orientation. Due to recent anomalous data, we are currently developing and testing computational electromagnetic models to explain their loss in transmission. From our models and a vector network analyzer used, we have concluded that unremoved metal and absorbed water cannot explain our data. We believe the information gathered by the project will provide a greater understanding of the galactic foreground and sources and help plan future missions.