Instrumental and analytic methods for bolometric polarimetry

¹ Division of Physics, Math, and Astronomy, California Institute of Technology, USA e-mail: wcj@astro.caltech.edu
² Physics Department, Case Western Reserve University, USA
³ Infrared Processing and Analysis Center, California Institute of Technology, USA
⁴ Department of Physics, Imperial College London, UK
⁵ Department of Physics, University of California, Santa Barbara, USA
⁶ Canadian Institute for Theoretical Astrophysics, University of Toronto, Canada
⁷ Department of Physics, University of Toronto, Canada
⁸ Department of Astronomy and Astrophysics, University of Toronto, Canada

Received: 26 June 2006
Accepted: 16 May 2007

Abstract

Aims.We discuss instrumental and analytic methods that have been developed for the first generation of bolometric cosmic microwave background (CMB) polarimeters. The design, characterization, and analysis of data obtained using Polarization Sensitive Bolometers (PSBs) are described in detail. This is followed by a brief study of the effect of various polarization modulation techniques on the recovery of sky polarization from scanning polarimeter data.

Methods.Having been successfully implemented on the sub-orbital BOOMERANG experiment, PSBs are currently operational in two terrestrial CMB polarization experiments (QUaD and the Robinson Telescope). We investigate two approaches to the analysis of data from these experiments, using realistic simulations of time ordered data to illustrate the impact of instrumental effects on the fidelity of the recovered polarization signal.

Results.We find that the analysis of difference time streams takes full advantage of the high degree of common mode rejection afforded by the PSB design. In addition to the observational efforts currently underway, this discussion is directly applicable to the PSBs that constitute the polarized capability of the Planck HFI instrument.