SPIDER: a balloon-borne CMB polarimeter for large angular scales

TL;DR

SPIDER is a balloon-borne CMB polarimeter designed to map polarization at large angular scales with high sensitivity, utilizing multiple telescopes and advanced detectors to probe inflationary gravitational waves.

Contribution

This paper introduces the SPIDER instrument, combining multiple telescopes and large-format bolometers with polarization modulation for improved CMB polarization measurements.

Findings

First flight planned for December 2011 in Antarctica

Maps 8% of the sky with high sensitivity to inflationary signals

Serves as technology demonstration for future satellite missions

Abstract

We describe SPIDER, a balloon-borne instrument to map the polarization of the millimeter-wave sky with degree angular resolution. Spider consists of six monochromatic refracting telescopes, each illuminating a focal plane of large-format antenna-coupled bolometer arrays. A total of 2,624 superconducting transition-edge sensors are distributed among three observing bands centered at 90, 150, and 280 GHz. A cold half-wave plate at the aperture of each telescope modulates the polarization of incoming light to control systematics. Spider's first flight will be a 20-30-day Antarctic balloon campaign in December 2011. This flight will map \sim8% of the sky to achieve unprecedented sensitivity to the polarization signature of the gravitational wave background predicted by inflationary cosmology. The Spider mission will also serve as a proving ground for these detector technologies in preparation for a future satellite mission.