Optical Characterization of the BICEP3 CMB Polarimeter at the South Pole
Abstract
BICEP3 is a small-aperture refracting cosmic microwave background (CMB) telescope designed to make sensitive polarization maps in pursuit of a potential B-mode signal from inflationary gravitational waves. It is the latest in the BICEP/Keck Array series of CMB experiments at the South Pole, which has provided the most stringent constraints on inflation to date. For the 2016 observing season, BICEP3 was outfitted with a full suite of 2400 optically coupled detectors operating at 95 GHz. In these proceedings we report on the far field beam performance using calibration data taken during the 2015-2016 summer deployment season in situ with a thermal chopped source. We generate high-fidelity per-detector beam maps, show the array-averaged beam profile, and characterize the differential beam response between co-located, orthogonally polarized detectors which contributes to the leading instrumental systematic in pair differencing experiments. We find that the levels of differential pointing, beamwidth, and ellipticity are similar to or lower than those measured for BICEP2 and Keck Array. The magnitude and distribution of BICEP3's differential beam mismatch - and the level to which temperature-to-polarization leakage may be marginalized over or subtracted in analysis - will inform the design of next-generation CMB experiments with many thousands of detectors.
Keywords
Cite
@article{arxiv.1607.04567,
title = {Optical Characterization of the BICEP3 CMB Polarimeter at the South Pole},
author = {K. S. Karkare and P. A. R. Ade and Z. Ahmed and K. D. Alexander and M. Amiri and D. Barkats and S. J. Benton and C. A. Bischoff and J. J. Bock and H. Boenish and R. Bowens-Rubin and I. Buder and E. Bullock and V. Buza and J. Connors and J. P. Filippini and S. T. Fliescher and J. A. Grayson and M. Halpern and S. A. Harrison and G. C. Hilton and V. V. Hristov and H. Hui and K. D. Irwin and J. H. Kang and E. Karpel and S. Kefeli and S. A. Kernasovskiy and J. M. Kovac and C. L. Kuo and E. M. Leitch and M. Lueker and K. G. Megerian and V. Monticue and T. Namikawa and C. B. Netterfield and H. T. Nguyen and R. O'Brient and R. W. Ogburn and C. Pryke and C. D. Reintsema and S. Richter and M. T. St. Germaine and R. Schwarz and C. D. Sheehy and Z. K. Staniszewski and B. Steinbach and G. P. Teply and K. L. Thompson and J. E. Tolan and C. Tucker and A. D. Turner and A. G. Vieregg and A. Wandui and A. Weber and J. Willmert and C. L. Wong and W. L. K. Wu and K. W. Yoon},
journal= {arXiv preprint arXiv:1607.04567},
year = {2017}
}
Comments
17 pages, 9 figures. Presented at SPIE Astronomical Telescopes and Instrumentation Conference 9914: Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VIII, June 2016