Improved polarization calibration of the BICEP3 CMB polarimeter at the South Pole

J. Cornelison, C. Vergès, P. A.R. Ade, Z. Ahmed, M. Amiri, D. Barkats, R. Basu Thakur, D. Beck, C. A. Bischoff, J. J. Bock, V. Buza, James R Cheshire, J. Connors, Mike Crumrine, A. J. Cukierman, E. V. Denison, M. I. Dierickx, L. Duband, M. Eiben, S. FatigoniJ. P. Filippini, C. Giannakopoulos, N. Goeckner-Wald, D. C. Goldfinger, J. Grayson, P. K. Grimes, G. Hall, G. Halal, M. Halpern, E. Hand, S. A. Harrison, S. Henderson, S. R. Hildebrandt, G. C. Hilton, J. Hubmayr, H. Hui, K. D. Irwin, J. Kang, K. S. Karkare, S. Kefeli, J. M. Kovac, C. L. Kuo, Kenny Lau, E. M. Leitch, A. Lennox, T. Liu, K. Look, K. G. Megerian, L. Minutolo, L. Moncelsi, Y. Nakato, T. Namikawa, H. T. Nguyen, R. O'Brient, S. Palladino, M. A. Petroff, T. Prouve, C. Pryke, B. Racine, C. D. Reintsema, M. Salatino, A. Schillaci, B. L. Schmitt, B. Singari, A. Soliman, T. St. Germaine, B. Steinbach, R. V. Sudiwala, K. L. Thompson, C. Tsai, C. Tucker, A. D. Turner, C. Umiltà, A. G. Vieregg, A. Wandui, A. C. Weber, D. V. Wiebe, Justin B Willmert, W. L.K. Wu, H. Yang, K. W. Yoon, E. Young, C. Yu, L. Zeng, C. Zhang, S. Zhang

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


The BICEP3 Polarimeter is a small aperture, refracting telescope, dedicated to the observation of the Cosmic Microwave Background (CMB) at 95GHz. It is designed to target degree angular scale polarization patterns, in particular the very-much-sought-After primordial B-mode signal, which is a unique signature of cosmic inflation. The polarized signal from the sky is reconstructed by differencing co-localized, orthogonally polarized superconducting Transition Edge Sensor (TES) bolometers. In this work, we present absolute measurements of the polarization response of the detectors for more than approximately 800 functioning detector pairs of the BICEP3 experiment, out of a total of approximately 1000. We use a specifically designed Rotating Polarized Source (RPS) to measure the polarization response at multiple source and telescope boresight rotation angles, to fully map the response over 360 degrees. We present here polarization properties extracted from on-site calibration data taken in January 2022. A similar calibration campaign was performed in 2018, but we found that our constraint was dominated by systematics on the level of approximately 0.5°. After a number of improvements to the calibration set-up, we are now able to report a significantly lower level of systematic contamination. In the future, such precise measurements will be used to constrain physics beyond the standard cosmological model, namely cosmic birefringence.

Original languageEnglish (US)
Title of host publicationMillimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI
EditorsJonas Zmuidzinas, Jian-Rong Gao
ISBN (Electronic)9781510653610
StatePublished - 2022
EventMillimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI 2022 - Montreal, Canada
Duration: Jul 17 2022Jul 22 2022

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceMillimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI 2022

Bibliographical note

Funding Information:
The BICEP/Keck project (including BICEP2, BICEP3 and BICEP Array) have been made possible through a series of grants from the National Science Foundation including 0742818, 0742592, 1044978, 1110087, 1145172, 1145143, 1145248, 1639040, 1638957, 1638978, 1638970, 1726917, 1313010, 1313062, 1313158, 1313287, 0960243, 1836010, 1056465, & 1255358 and by the Keck Foundation. The development of antenna-coupled detector technology was supported by the Jet Propulsion Laboratory Research and Technology Development Fund and NASA Grants 06-ARPA206-0040, 10-SAT10-0017, 12-SAT12-0031, 14-SAT14-0009, 16-SAT16-0002, & 18-SAT18-0017. Focal plane development and testing were supported by the Gordon and Betty Moore Foundation at the California Institute of Technology. Readout electronics were supported by a Canada Foundation for Innovation grant to the University of British Columbia. The computations in this paper were run on the Cannon cluster supported by the FAS Science Division Research Computing Group at Harvard University. The analysis effort at Stanford University and the SLAC National Accelerator Laboratory was partially supported by the Department of Energy, Contract DE-AC02-76SF00515. We thank the staff of the U.S. Antarctic Program and in particular the South Pole Station without whose help this research would not have been possible. Tireless administrative support was provided by Amy Dierker, Kathy Deniston, Sheri Stoll, Irene Coyle, Donna Hernandez, and Dana Volponi.

Publisher Copyright:
© 2022 SPIE.


  • Calibration
  • Cosmic Birefringence
  • Cosmic Microwave Background
  • Polarization


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