Pre-flight integration and characterization of the SPIDER balloon-borne telescope

TL;DR

This paper details the integration and pre-flight testing of the SPIDER balloon-borne polarimeter, which aims to measure the B-mode polarization of the cosmic microwave background to detect primordial gravitational waves.

Contribution

It reports the successful integration and characterization of a multi-telescope instrument designed for CMB polarization measurements, with significant sensitivity improvements over previous missions.

Findings

SPIDER will map 7.5% of the sky with high sensitivity at 94 and 150 GHz.

The instrument is ready for a December 2014 Antarctic flight.

Instrument sensitivity is expected to be limited by astrophysical foregrounds, not hardware.

Abstract

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.