Bicep/Keck XV: The Bicep3 Cosmic Microwave Background Polarimeter and the First Three-year Data Set

• Published in: The Astrophysical Journal
• Main Authors: Ade, P. A. R., Ahmed, Z., Amiri, M., Barkats, D., Thakur, R. Basu, Bischoff, C. A., Beck, D., Bock, J. J., Boenish, H., Bullock, E., Buza, V., Cheshire, J. R., IV, Connors, J., Cornelison, J., Crumrine, M., Cukierman, A., Denison, E. V., Dierickx, M., Duband, L., Eiben, M., Fatigoni, S., Filippini, J. P., Fliescher, S., Goeckner-Wald, N., Goldfinger, D. C., Grayson, J., Grimes, P., Hall, G., Halal, G., Halpern, M., Hand, E., Harrison, S., Henderson, S., Hildebrandt, S. R., Hilton, G. C., Hubmayr, J., Hui, H., Irwin, K. D., Kang, J., Karkare, K. S., Karpel, E., Kefeli, S., Kernasovskiy, S. A., Kovac, J. M., Kuo, C. L., Lau, K., Leitch, E. M., Lennox, A., Megerian, K. G., Minutolo, L., Moncelsi, L., Nakato, Y., Namikawa, T., Nguyen, H. T., O'Brient, R., Ogburn, R. W., IV, Palladino, S., Prouve, T., Pryke, C., Racine, B., Reintsema, C. D., Richter, S., Schillaci, A., Schwarz, R., Schmitt, B. L., Sheehy, C. D., Soliman, A., St. Germaine, T., Steinbach, B., Sudiwala, R. V., Teply, G. P., Thompson, K. L., Tolan, J. E., Tucker, C., Turner, A. D., Umiltà , C., Vergès, C., Vieregg, A. G., Wandui, A., Weber, A. C., Wiebe, D. V., Willmert, J., Wong, C. L., Wu, W. L. K., Yang, H., Yoon, K. W., Young, E., Yu, C., Zeng, L., Zhang, C., Zhang, S., BICEP/Keck Collaboration
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Astronomical Society 2022
• Subjects: Cosmic microwave background radiation; Polarimeters; Gravitational waves; Cosmic inflation; Space and Planetary Science; Astronomy and Astrophysics; South pole
• Online Access: https://doi.org/10.3847/1538-4357/ac4886

We report on the design and performance of the Bicep3 instrument and its first three-year data set collected from 2016 to 2018. Bicep3 is a 52 cm aperture refracting telescope designed to observe the polarization of the cosmic microwave background (CMB) on degree angular scales at 95 GHz. It started science observation at the South Pole in 2016 with 2400 antenna-coupled transition-edge sensor bolometers. The receiver first demonstrated new technologies such as large-diameter alumina optics, Zotefoam infrared filters, and flux-activated SQUIDs, allowing ∼10× higher optical throughput compared to the Keck design. Bicep3 achieved instrument noise equivalent temperatures of 9.2, 6.8, and 7.1 μK_(CMB) √s and reached Stokes Q and U map depths of 5.9, 4.4, and 4.4 μK arcmin in 2016, 2017, and 2018, respectively. The combined three-year data set achieved a polarization map depth of 2.8 μK arcmin over an effective area of 585 square degrees, which is the deepest CMB polarization map made to date at 95 GHz. © 2022. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2021 September 30; revised 2021 December 22; accepted 2022 January 3; published 2022 March 7. Bicep/Keck has 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, and 1836010 and by the Keck Foundation. The construction of the Bicep3 receiver was supported by the Department of Energy, Laboratory Directed Research and Development program at SLAC National Accelerator Laboratory, under contract DE-AC02-76SF00515. The development of antenna-coupled detector technology was supported by the JPL Research and Technology Development Fund and grant Nos. ...