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Proceedings Paper

The quasi-optical design of the QUaD Telescope
Author(s): Gary Cahill; Creidhe O'Sullivan; J. Anthony Murphy; William Lanigan; Emily Gleeson; Peter A. R. Ade; James J. Bock; Melanie Bowden; John E. Carlstrom; Sarah E. Church; Ken Ganga; Walter Gear; John Harris; James Hinderks; Wayne Hu; John Kovac; Andrew Lange; Erik M. Leitch; Bruno Maffei; Olivier Mallie; Simon Melhuish; Angiola Orlando; Giampaolo Pisano; Lucio Piccirillo; Clem Pryke; Ben Rusholme; Andy Taylor; Keith L. Thompson; Michael Zemcov
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Paper Abstract

QUaD is a ground-based high-resolution (up to l ≈ 2500) instrument designed to map the polarisation of the Cosmic Microwave Background and to measure its E-mode and B-mode polarisation power spectra. QUaD comprises a bolometric array receiver (100 and 150 GHz) and re-imaging optics on a 2.6-m Cassegrain telescope 2. It will operate for two years and begin observations in 2005. CMB polarisation measurements will require not only a significant increase in sensitivity over earlier experiments but also a better understanding and control of systematic effects particularly those that contribute to the polarised signal. To this end we have undertaken a comprehensive quasi-optical analysis of the QUaD telescope. In particular we have modelled the effects of diffraction on beam propagation through the system. The corrugated feeds that couple radiation from the telescope to phase-sensitive bolometers need to have good beam symmetry and low sidelobe levels over the required bandwidth. It is especially important that the feed horns preserve the polarisation orientation of the incoming fields. We have used an accurate mode-matching model to design such feed horns. In this paper we present the diffraction analysis of the QUaD front-end optics as well as the electromagnetic design and testing of the QUaD corrugated feeds.

Paper Details

Date Published: 8 October 2004
PDF: 11 pages
Proc. SPIE 5498, Millimeter and Submillimeter Detectors for Astronomy II, (8 October 2004); doi: 10.1117/12.551680
Show Author Affiliations
Gary Cahill, National Univ. of Ireland/Maynooth (Ireland)
Creidhe O'Sullivan, National Univ. of Ireland/Maynooth (Ireland)
J. Anthony Murphy, National Univ. of Ireland/Maynooth (Ireland)
William Lanigan, National Univ. of Ireland/Maynooth (Ireland)
Emily Gleeson, National Univ. of Ireland/Maynooth (Ireland)
Peter A. R. Ade, Cardiff Univ. (United Kingdom)
James J. Bock, Jet Propulsion Lab. (United States)
Melanie Bowden, Cardiff Univ. (United Kingdom)
John E. Carlstrom, Univ. of Chicago (United States)
Sarah E. Church, Stanford Univ. (United States)
Ken Ganga, California Institute of Technology (United States)
Walter Gear, Cardiff Univ. (United Kingdom)
John Harris, Cardiff Univ. (United Kingdom)
James Hinderks, Stanford Univ. (United States)
Wayne Hu, Univ. of Chicago (United States)
John Kovac, Univ. of Chicago (United States)
Andrew Lange, California Institute of Technology (United States)
Erik M. Leitch, Univ. of Chicago (United States)
Bruno Maffei, Cardiff Univ. (United Kingdom)
Olivier Mallie, Cardiff Univ. (United Kingdom)
Simon Melhuish, Cardiff Univ. (United Kingdom)
Angiola Orlando, Cardiff Univ. (United Kingdom)
Giampaolo Pisano, Cardiff Univ. (United Kingdom)
Lucio Piccirillo, Cardiff Univ. (United Kingdom)
Clem Pryke, Univ. of Chicago (United States)
Ben Rusholme, Stanford Univ. (United States)
Andy Taylor, Univ. of Edinburgh (United Kingdom)
Keith L. Thompson, Stanford Univ. (United States)
Michael Zemcov, Cardiff Univ. (United Kingdom)

Published in SPIE Proceedings Vol. 5498:
Millimeter and Submillimeter Detectors for Astronomy II
Jonas Zmuidzinas; Wayne S. Holland; Stafford Withington, Editor(s)

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