Use of superconducting bearings to measure the polarization of the cosmic microwave background radiation.

Conference · Wed Aug 21 04:00:00 EDT 2002

OSTI ID:799835

Hanany, S; Matsumura, T; Johnson, B; Jones, T; Hull, J R; Ma, K B

Measurements of the polarization of the cosmic microwave background (CMB) radiation are expected to significantly increase our understanding of the early universe. We present a design for a CMB polarimeter in which a cryogenically cooled half wave plate rotates by means of a high-temperature superconducting (HTS) bearing. The design is optimized for implementation in MAXIPOL, a balloon-borne CMB polarimeter. A prototype bearing, consisting of commercially available ring-shaped permanent magnet and an array of YBCO bulk HTS material, has been constructed. We report on measurements of the coefficient of friction as a function of temperature between 15 and 80 K, of rotation frequency between 0.3 and 3.5 Hz, of levitation distance between 6 and 10 mm, and of ambient pressure between 1 and 10{sup -7} torr. The low rotational drag of the HTS bearing allows rotations for long periods of time with minimal input power and negligible wear and tear thus making this technology suitable for a future satellite mission.

• Research Organization: Argonne National Lab., IL (US)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 799835
• Report Number(s): ANL/ET/CP-106853
• Country of Publication: United States
• Language: English

Related Subjects

47 OTHER INSTRUMENTATION
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BACKGROUND RADIATION
COSMIC RADIATION
DESIGN
MAGNETIC BEARINGS
POLARIMETERS
POLARIZATION
SUPERCONDUCTING DEVICES