A cryogenic half-wave plate polarimeter using a superconducting magnetic bearing

Jeff Klein, Asad Aboobaker, Peter Ade, François Aubin, Carlo Baccigalupi, Chaoyun Bao, Julian Borrill, Daniel Chapman, Joy Didier, Matt Dobbs, Benjamin Gold, Will Grainger, Shaul Hanany, Johannes Hubmayr, Seth Hillbrand, Julien Grain, Andrew Jaffe, Bradley Johnson, Terry Jones, Theodore KisnerAndrei Korotkov, Sam Leach, Adrian Lee, Lome Levinson, Michele Limon, Kevin MacDermid, Tomotake Matsumura, Amber Miller, Michael Milligan, Enzo Pascale, Daniel Polsgrove, Nicolas Ponthieu, Kate Raach, Britt Reichborn-Kjennerud, Ilan Sagiv, Radek Stompor, Huan Tran, Matthieu Trist Ram, Gregory S. Tucker, Amit Yadav, Matias Zaldarriaga, Kyle Zilie

Research output: Chapter in Book/Report/Conference proceedingConference contribution

18 Scopus citations


We present the design and measured performance of the superconducting magnetic bearing (SMB) that was used successfully as the rotation mechanism in the half-wave plate Polarimeter of the E and B Experiment (EBEX) during its North American test flight. EBEX is a NASA-supported balloon-borne experiment that is designed to measure the polarization of the cosmic microwave background. In this implementation the half-wave plate is mounted to the rotor of an SMB that is operating at a sink temperature of 4 K. We demonstrate robust, remote operation on a balloon-borne payload, with angular encoding accuracy of 0.01°. We find rotational speed variations to be 0.2% RMS. We measure vibrational modes and find them to be consistent with a simple SMB model. We search for but do not find magnetic field interference in the detectors and readout. We set an upper limit of 3% of the receiver noise level after 5 minutes of integration on such interference. At 2 Hz rotation we measure a power dissipation of 56 mW. If this power dissipation is reduced, such an SMB implementation is a candidate for low-noise space applications because of the absence of stick-slip friction and low wear.

Original languageEnglish (US)
Title of host publicationCryogenic Optical Systems and Instruments XIII
ISBN (Print)9780819487605
StatePublished - 2011
EventCryogenic Optical Systems and Instruments XIII - San Diego, CA, United States
Duration: Aug 24 2011Aug 25 2011

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


ConferenceCryogenic Optical Systems and Instruments XIII
Country/TerritoryUnited States
CitySan Diego, CA


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