The Q/U imaging experiment instrument

Journal article

The Q/U Imaging ExperimenT (QUIET) is designed to measure polarization in the cosmic microwave background, targeting the imprint of inflationary gravitational waves at large angular scales(~1°). Between 2008 October and 2010 December, two independent receiver arrays were deployed sequentially on a 1.4 m side-fed Dragonian telescope. The polarimeters that form the focal planes use a compact design based on high electron mobility transistors (HEMTs) that provides simultaneous measurements of the Stokes parameters Q, U, and I in a single module. The 17-element Q-band polarimeter array, with a central frequency of 43.1 GHz, has the best sensitivity (69 μKs1/2) and the lowest instrumental systematic errors ever achieved in this band, contributing to the tensor-to-scalar ratio at r < 0.1. The 84-element W-band polarimeter array has a sensitivity of 87 μKs1/2 at a central frequency of 94.5 GHz. It has the lowest systematic errors to date, contributing at r < 0.01. The two arrays together cover multipoles in the range ℓ ~ 25-975. These are the largest HEMT-based arrays deployed to date. This article describes the design, calibration, performance, and sources of systematic error of the instrument.

Authors: QUIET Collaboration; Bischoff, C; Brizius, A; Buder, I; Chinone, Y

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Astronomical Society
• Journal: Astrophysical Journal
• Volume: 768
• Issue: 1
• Pages: 1-28
• Publication date: 2013-04-09
• Acceptance date: 2013-02-08
• DOI: 10.1088/0004-637X/768/1/9
• EISSN: 1538-4357
• ISSN: 0004-637X
• Keywords: instrumentation: detectors; cosmic background radiation; instrumentation: polarimeters; cosmology: observations; SBTMR; telescopes