Thesis Defense – Ms. Johanna Nagy

Optical Development for the SPIDER Balloon-Borne CMB Polarimeter

The generation of a stochastic background of gravitational waves is a key prediction of inflation. At large angular scales, these gravitational waves imprint a B-mode polarization pattern in the Cosmic Microwave Background, providing a new window into the physics of the early universe and helping to constrain and distinguish between inflationary models. SPIDER is a balloon-borne telescope uniquely optimized to search for the inflationary B-mode signature. Over the course of two Antarctic flights, SPIDER will make polarization maps over 10% of the sky in three frequency bands with degree-scale angular resolution. The SPIDER optics are designed to take advantage of the low atmospheric loading and large sky coverage accessible from the ballooning platform through a combination of high optical efficiency, low in-band loading, and strong sidelobe rejection. These goals are applied to the design, fabrication, and testing of many optical components including forebaffles, windows, and half-wave plate polarization modulators. A review of instrument performance is presented as a validation of the optical system, including the polarization angle calibration and preliminary data analysis from the first flight in January 2015. Preparations for a second flight in December 2017 are currently underway.

August 23, 2016

The Miller Room – 10:00 a.m.

Advisor: John Ruhl