Pre-flight integration and characterization of the SPIDER balloon-borne
  telescope
  We present the results of integration and characterization of the SPIDER
instrument after the 2013 pre-flight campaign. SPIDER is a balloon-borne
polarimeter designed to probe the primordial gravitational wave signal in the
degree-scale $B$-mode polarization of the cosmic microwave background. With six
independent telescopes housing over 2000 detectors in the 94 GHz and 150 GHz
frequency bands, SPIDER will map 7.5% of the sky with a depth of 11 to 14
$\mu$K$\cdot$arcmin at each frequency, which is a factor of $\sim$5 improvement
over Planck. We discuss the integration of the pointing, cryogenic,
electronics, and power sub-systems, as well as pre-flight characterization of
the detectors and optical systems. SPIDER is well prepared for a December 2014
flight from Antarctica, and is expected to be limited by astrophysical
foreground emission, and not instrumental sensitivity, over the survey region.
