5.3 Saskatoon

This experiment is a ground-based telescope located in Saskatoon, Canada. A cooled HEMT receiver with six channels is used to span the frequency range 26 to 46 GHz. The chopping strategy is quite complex, and can be used to synthesise ‘window functions’ appropriate to a range of angular scales. The beam sizes used range from ∼ 1.5° at the lowest frequency to ∼ 0.5° at the highest. The analysis of observations of a 24 hour RA strip at declination +85.1° is described in Wollack et al. (1993) [99] and Netterfield et al. (1995) [64], indicating a detection of primordial anisotropy. More recently in Netterfield et al. (1997) [63], exciting results have been presented which show not just a detection, but for the first time for a switched-beam instrument, evidence for the form of the power spectrum itself on the angular scales probed. The final map after 3 years of data from this experiment is shown in Figure 13View Image
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Figure 13: Saskatoon 3 year map showing region analysed as compared to the COBE full sky coverage.
and the power spectrum from this map will be used below, in comparison with theoretical predictions. We note here that there is currently an overall scaling uncertainty in the Saskatoon results of ±14%, due to calibration uncertainties. Recent analysis of the Saskatoon data (Knox, in prep.) appear to show that the previous calibration is an underestimate of the true level of the Saskatoon data. This would make the Doppler peak even higher and lower the value of H ∘ found below.
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