SPIDER: a balloon-borne CMB polarimeter for large angular scales
  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. 
J.P. Filippini, P.A.R. Ade, M. Amiri, S.J. Benton, R. Bihary, J.J.   Bock, J.R. Bond, J.A. Bonetti, S.A. Bryan, B. Burger, H...
astro-ph.CO astro-ph.IM