Receiver development for BICEP Array, a next-generation CMB polarimeter at the South Pole

• Main Authors: Moncelsi, L., Ade, P. A. R., Ahmed, Z., Amiri, M., Barkats, D., Thakur, R. Basu, Bischoff, C. A., Bock, J. J., Buza, V., Cheshire, J., Connors, J., Cornelison, J., Crumrine, M., Cukierman, A., Denison, E. V., Dierickx, M., Duband, L., Eiben, M., Fatigoni, S., Filippini, J. P., Goeckner-Wald, N., Goldfinger, D. C., Grayson, J., Grimes, P., Hall, G., Halpern, M., Harrison, S., Henderson, S., Hildebrandt, S. R., Hilton, G. C., Hubmayr, J., Hui, H., Irwin, K. D., Kang, J., Karkare, K. S., Kefeli, S., Kovac, J. M., Kuo, C. L., Lau, K., Leitch, E. M., Megerian, K. G., Minutolo, L., Nakato, Y., Namikawa, T., Nguyen, H. T., O'Brient, R., Palladino, S., Precup, N., Prouve, T., Pryke, C., Racine, B., Reintsema, C. D., Schillaci, A., Schmitt, B. L., Soliman, A., Germaine, T. St., Steinbach, B., Sudiwala, R. V., Thompson, K. L., Tucker, C., Turner, A. D., Umiltà, C., Vieregg, A. G., Wandui, A., Weber, A. C., Wiebe, D. V., Willmert, J., Wu, W. L. K., Yang, E., Yoon, K. W., Young, E., Yu, C., Zeng, L., Zhang, C., Zhang, S.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: arXiv 2020
• Subjects: Instrumentation and Methods for Astrophysics astro-ph.IM; Cosmology and Nongalactic Astrophysics astro-ph.CO; Instrumentation and Detectors physics.ins-det; FOS Physical sciences; South Pole; Curl; South pole
• Online Access: https://dx.doi.org/10.48550/arxiv.2012.04047; https://arxiv.org/abs/2012.04047

A detection of curl-type ($B$-mode) polarization of the primary CMB would be direct evidence for the inflationary paradigm of the origin of the Universe. The BICEP/Keck Array (BK) program targets the degree angular scales, where the power from primordial $B$-mode polarization is expected to peak, with ever-increasing sensitivity and has published the most stringent constraints on inflation to date. BICEP Array (BA) is the Stage-3 instrument of the BK program and will comprise four BICEP3-class receivers observing at 30/40, 95, 150 and 220/270 GHz with a combined 32,000+ detectors; such wide frequency coverage is necessary for control of the Galactic foregrounds, which also produce degree-scale $B$-mode signal. The 30/40 GHz receiver is designed to constrain the synchrotron foreground and has begun observing at the South Pole in early 2020. By the end of a 3-year observing campaign, the full BICEP Array instrument is projected to reach $σ_r$ between 0.002 and 0.004, depending on foreground complexity and degree of removal of $B$-modes due to gravitational lensing (delensing). This paper presents an overview of the design, measured on-sky performance and calibration of the first BA receiver. We also give a preview of the added complexity in the time-domain multiplexed readout of the 7,776-detector 150 GHz receiver. : Proceedings of SPIE 2020 (AS111). This article supersedes arXiv:1808.00568 and arXiv:2002.05228