Optical performance of the BICEP2 Telescope at the South Pole

Randol W. Aikin, P. A. Ade, S. Benton, J. J. Bock, J. A. Bonetti, J. A. Brevik, C. D. Dowell, L. Duband, J. P. Filippini, S. R. Golwala, M. Halpern, V. V. Hristov, K. Irwin, J. P. Kaufman, B. G. Keating, J. M. Kovac, C. L. Kuo, A. E. Lange, C. B. Netterfield, H. T. NguyenR. W. Ogburn Iv, A. Orlando, C. Pryke, S. Richter, J. E. Ruhl, M. C. Runyan, C. Sheehy, S. A. Stokes, R. Sudiwala, G. P. Teply, J. E. Tolan, A. D. Turner, P. Wilson, C. L. Wong

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

Abstract

Bicep2 deployed to the South Pole during the 2009-2010 austral summer, and is now mapping the polarization of the cosmic microwave background (CMB), searching for evidence of inflationary cosmology. Bicep2 belongs to a new class of telescopes including Keck (ground-based) and Spider (balloon-borne) that follow on Bicep's strategy of employing small, cold, on-axis refracting optics. This common design provides key advantages ideal for targeting the polarization signature from inflation, including: (i) A large field of view, allowing substantial light collecting power despite the small aperture, while still resolving the degree-scale polarization of the CMB; (ii) liquid helium-cooled optics and cold stop, allowing for low, stable instrument loading; (iii) the ability to rotate the entire telescope about the boresight; (iv) a baffled primary aperture, reducing sidelobe pickup; and (v) the ability to characterize the far field optical performance of the telescope using ground-based sources. We describe the last of these advantages in detail, including our efforts to measure the main beam shape, beammatch between orthogonally-polarized pairs, polarization efficiency and response angle, sidelobe pickup, and ghost imaging. We do so with ground-based polarized microwave sources mounted in the far field as well as with astronomical calibrators. Ultimately, Bicep2's sensitivity to CMB polarization from inflation will rely on precise calibration of these beam features.

Original languageEnglish (US)
Title of host publicationMillimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V
DOIs
StatePublished - Sep 7 2010
Externally publishedYes
EventMillimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V - San Diego, CA, United States
Duration: Jun 29 2010Jul 2 2010

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume7741
ISSN (Print)0277-786X

Other

OtherMillimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V
CountryUnited States
CitySan Diego, CA
Period6/29/107/2/10

Keywords

  • Bicep
  • Bicep2
  • Cosmic microwave background
  • Keck
  • Polarization
  • Spider

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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  • Cite this

    Aikin, R. W., Ade, P. A., Benton, S., Bock, J. J., Bonetti, J. A., Brevik, J. A., Dowell, C. D., Duband, L., Filippini, J. P., Golwala, S. R., Halpern, M., Hristov, V. V., Irwin, K., Kaufman, J. P., Keating, B. G., Kovac, J. M., Kuo, C. L., Lange, A. E., Netterfield, C. B., ... Wong, C. L. (2010). Optical performance of the BICEP2 Telescope at the South Pole. In Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V [77410V] (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 7741). https://doi.org/10.1117/12.857868