BICEP3: A 95GHz Refracting Telescope for Degree-Scale CMB Polarization

• Published in: SPIE Proceedings, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII
• Main Authors: Ahmed, Z., Amiri, M., Benton, S. J., Bock, J. J., Bowens-Rubin, R, Buder, I, Bullock, E., Connors, Jake Anthony, Filippini, J. P., Grayson, J. A., Halpern, M., Hilton, G. C., Hristov, V. V., Hui, H., Irwin, K. D., Kang, J., Karkare, Kirit Sukrit, Karpel, E., Kovac, John M, Kuo, C. L., Netterfield, C. B., Nguyen, H. T., O, R., Ogburn, R. W., Pryke, C, Reintsema, C. D., Richter, Sonja Valeska, Thompson, K. L., Turner, A. D., Vieregg, A. G., Wu, W. L. K., Yoon, K. W.
• Format: Conference Object
• Language: English
• Published: International Society for Optics and Photonics 2014
• Subjects: Inflation; Gravitational Waves; Cosmic Microwave Background; Polarization; BICEP; Keck Array; South Pole; South pole
• Online Access: http://nrs.harvard.edu/urn-3:HUL.InstRepos:42667704; https://doi.org/10.1117/12.2057224

Bicep3 is a 550 mm-aperture refracting telescope for polarimetry of radiation in the cosmic microwave background at 95 GHz. It adopts the methodology of Bicep1, Bicep2 and the Keck Array experiments — it possesses sufficient resolution to search for signatures of the inflation-induced cosmic gravitational-wave background while utilizing a compact design for ease of construction and to facilitate the characterization and mitigation of systematics. However, Bicep3 represents a significant breakthrough in per-receiver sensitivity, with a focal plane area 5× larger than a Bicep2/Keck Array receiver and faster optics (f /1.6 vs. f /2.4). Large-aperture infrared-reflective metal-mesh filters and infrared-absorptive cold alumina filters and lenses were developed and implemented for its optics. The camera consists of 1280 dual-polarization pixels; each is a pair of orthogonal antenna arrays coupled to transition-edge sensor bolometers and read out by multiplexed SQUIDs. Upon deployment at the South Pole during the 2014-15 season, Bicep3 will have survey speed comparable to Keck Array 150 GHz (2013), and will significantly enhance spectral separation of primordial B-mode power from that of possible galactic dust contamination in the Bicep2 observation patch. Astronomy Accepted Manuscript