학술논문
Intensity-Coupled-Polarization in Instruments with a Continuously Rotating Half-Wave Plate
Document Type
Working Paper
Author
Didier, Joy; Miller, Amber D.; Araujo, Derek; Aubin, François; Geach, Christopher; Johnson, Bradley; Korotkov, Andrei; Raach, Kate; Westbrook, Benjamin; Young, Karl; Aboobaker, Asad M.; Ade, Peter; Baccigalupi, Carlo; Bao, Chaoyun; Chapman, Daniel; Dobbs, Matt; Grainger, Will; Hanany, Shaul; Helson, Kyle; Hillbrand, Seth; Hubmayr, Johannes; Jaffe, Andrew; Jones, Terry; Klein, Jeff; Lee, Adrian; Limon, Michele; MacDermid, Kevin; Milligan, Michael; Pascale, Enzo; Reichborn-Kjennerud, Britt; Sagiv, Ilan; Tucker, Carole; Tucker, Gregory S.; Zilic, Kyle
Source
ApJ 876 54 (2019)
Subject
Language
Abstract
We discuss a systematic effect associated with measuring polarization with a continuously rotating half-wave plate. The effect was identified with the data from the E and B Experiment (EBEX), which was a balloon-borne instrument designed to measure the polarization of the CMB as well as that from Galactic dust. The data show polarization fraction larger than 10\% while less than 3\% were expected from instrumental polarization. We give evidence that the excess polarization is due to detector non-linearity in the presence of a continuously rotating HWP. The non-linearity couples intensity signals into polarization. We develop a map-based method to remove the excess polarization. Applying this method for the 150 (250) GHz bands data we find that 81\% (92\%) of the excess polarization was removed. Characterization and mitigation of this effect is important for future experiments aiming to measure the CMB B-modes with a continuously rotating HWP.
Comment: 43 pages, 12 figures, submitted to the Astrophysical Journal
Comment: 43 pages, 12 figures, submitted to the Astrophysical Journal