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Proceedings Paper

A LEKID-based CMB instrument design for large-scale observations in Greenland
Author(s): D. C. Araujo; P. A. R. Ade; J. R. Bond; K. J. Bradford; D. Chapman; G. Che; P. K. Day; J. Didier; S. Doyle; H. K. Eriksen; D. Flanigan; C. E. Groppi; Seth N. Hillbrand; B. R. Johnson; G. Jones; Michele Limon; A. D. Miller; P. Mauskopf; H. McCarrick; T. Mroczkowski; B. Reichborn-Kjennerud; B. Smiley; Joshua Sobrin; I. K. Wehus; J. Zmuidzinas
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Paper Abstract

We present the results of a feasibility study, which examined deployment of a ground-based millimeter-wave polarimeter, tailored for observing the cosmic microwave background (CMB), to Isi Station in Greenland. The instrument for this study is based on lumped-element kinetic inductance detectors (LEKIDs) and an F/2.4 catoptric, crossed-Dragone telescope with a 500 mm aperture. The telescope is mounted inside the receiver and cooled to < 4 K by a closed-cycle 4He refrigerator to reduce background loading on the detectors. Linearly polarized signals from the sky are modulated with a metal-mesh half-wave plate that is rotated at the aperture stop of the telescope with a hollow-shaft motor based on a superconducting magnetic bearing. The modular detector array design includes at least 2300 LEKIDs, and it can be configured for spectral bands centered on 150 GHz or greater. Our study considered configurations for observing in spectral bands centered on 150, 210 and 267 GHz. The entire polarimeter is mounted on a commercial precision rotary air bearing, which allows fast azimuth scan speeds with negligible vibration and mechanical wear over time. A slip ring provides power to the instrument, enabling circular scans (360 degrees of continuous rotation). This mount, when combined with sky rotation and the latitude of the observation site, produces a hypotrochoid scan pattern, which yields excellent cross-linking and enables 34% of the sky to be observed using a range of constant elevation scans. This scan pattern and sky coverage combined with the beam size (15 arcmin at 150 GHz) makes the instrument sensitive to 5 < ` < 1000 in the angular power spectra.

Paper Details

Date Published: 19 August 2014
PDF: 15 pages
Proc. SPIE 9153, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII, 91530W (19 August 2014); doi: 10.1117/12.2056828
Show Author Affiliations
D. C. Araujo, Columbia Univ. (United States)
P. A. R. Ade, Cardiff Univ. (United Kingdom)
J. R. Bond, Canadian Institute for Theoretical Astrophysics, Univ. of Toronto (Canada)
K. J. Bradford, Arizona State Univ. (United States)
D. Chapman, Columbia Univ. (United States)
G. Che, Arizona State Univ. (United States)
P. K. Day, Jet Propulsion Lab. (United States)
J. Didier, Columbia Univ. (United States)
S. Doyle, Cardiff Univ. (United Kingdom)
H. K. Eriksen, Univ. of Oslo (Norway)
D. Flanigan, Columbia Univ. (United States)
C. E. Groppi, Arizona State Univ. (United States)
Seth N. Hillbrand, Columbia Univ. (United States)
California State Univ. (United States)
B. R. Johnson, Columbia Univ. (United States)
G. Jones, Columbia Univ. (United States)
Michele Limon, Columbia Univ. (United States)
A. D. Miller, Columbia Univ. (United States)
P. Mauskopf, Arizona State Univ. (United States)
H. McCarrick, Columbia Univ. (United States)
T. Mroczkowski, U.S. Naval Research Lab. (United States)
B. Reichborn-Kjennerud, Columbia Univ. (United States)
B. Smiley, Columbia Univ. (United States)
Joshua Sobrin, Columbia Univ. (United States)
I. K. Wehus, Univ. of Oslo (Norway)
J. Zmuidzinas, Jet Propulsion Lab. (United States)
California Institute of Technology (United States)

Published in SPIE Proceedings Vol. 9153:
Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII
Wayne S. Holland; Jonas Zmuidzinas, Editor(s)

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