DASI: A Degree Angular Scale Interferometer for Imaging Anisotropy in the Cosmic Microwave Background

N. W. Halverson, J. E. Carlstrom, M. Dragovan, W. L. Holzapfel, and J. Kovac


The Degree Angular Scale Interferometer (DASI) is a compact cm-wave interferometer designed to image anisotropy in the Cosmic Microwave Background (CMB) and to measure its angular power spectrum. The power spectrum will be densely sampled over the l range 160 to 710, corresponding to angular scales of 0.25 to 1.15 degrees. DASI consists of 13 elements. Each element consists of a 20-cm diameter lensed corrugated horn followed by a cooled low-noise HEMT amplifier operating from 26 - 36 GHz. All elements are mounted on a single alt-az mount, which fixes the projected baselines and obviates an IF tracking delay. The mount also includes rotation of the aperture plane along the line of sight to improve the u,v coverage and the control of instrumental systematics. The 10 GHz IF bandwidth will be correlated in 1 GHz bands to provide spectral index information. The instrument is scheduled to be completed in Summer 1998. After extensive testing it will be deployed at the South Pole for year-round operation starting in November 1999.

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  1. Introduction
  2. Array Configuration
  3. Optics
  4. Receivers
  5. Correlator
  6. Mount
  7. Ground Shields
  8. The Polar Site
  9. Acknowledgements and References

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Last modified Apr 23, 1998