Planck pre-launch status : High Frequency Instrument polarization calibration
Rosset, C ; Tristram, M ; Ponthieu, N ; et al. ; - ASI Sponsor
Jan - 2010

journal : Astronomy \& Astrophysics
type: Article Journal

The High Frequency Instrument of Planck will map the entire sky in the millimeter and sub-millimeter domain from 100 to 857 GHz with unprecedented sensitivity to polarization (P=T 4 106 for P either Q or U) at 100, 143, 217 and 353 GHz. It will lead to major improvements in the Cosmic Microwave Background anisotropies and polarized foreground signal. Planck will make a high resolution measurements of the E-mode spectrum (up to ` 1500) and will also play a prominent role in the quest for the discovery of the faint imprint of primordial gravitational waves on the CMB polarization. This paper addresses the e ects of calibration of both temperature (gain) and polarization (polarization eciency and detector orientation) into polarization measurements. The speci c requirements on the polarization parameters of the instrument are set and we reports on their pre- ight measurement on HFI bolometers. We present a semi-analytical method that exactly accounts for the scanning strategy of the instrument as well as the combination of di erent detectors. We use this method to propagate errors through the CMB angular power spectra in the particular case of Planck-HFI, and to derive the aforementioned constraints. We show that in order to limit the systematic error to 10\% of the cosmic variance of the E-mode power spectrum, uncertainties in gain, polarization eciency and detector orientation must be below 0.15\%, 0.3\% and 1 respectively. Pre-launch ground measurements reported in this paper already ful ll these requirements.

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