2017 upgrade and performance of BICEP3: a 95GHz refracting telescope for degree-scale CMB polarization

• Published in: Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX
• Main Authors: Kang, Jae Hwan, Ade, P.A. R., Ahmed, Z., Aikin, R.W., Alexander, K.D., Barkats, D., Benton, S.J., Bischoff, C.A., Bock, J.J., Boenish, H., Bowens-Rubin, R., Brevik, J.A., Buder, I., Bullock, E., Buza, V., Connors, J., Cornelison, J., Crill, B.P., Crumrine, M., Dierickx, M., Duband, L., Dvorkin, C., Filippini, J.P., Fliescher, S., Grayson, J.A., Hall, G., Halpern, M., Harrison, S., Hildebrandt, S.R., Hilton, G.C., Hui, H., Irwin, K.D., Karkare, K.S., Karpel, E., Kaufman, J.P., Keating, B.G., Kefeli, S., Kernasovskiy, S.A., Kovac, J.M., Kuo, C.L., Lau, K., Larsen, N.A., Leitch, E.M., Lueker, M., Megerian, K.G., Moncelsi, L., Namikawa, T., Netterfield, B., Nguyen, H.T., O'Brient, R.
• Other Authors: Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2018
• Subjects: Cosmic Microwave Background; Inflation; Gravitational Waves; Polarization; BICEP3; Keck Array; cosmic background radiation: polarization; beam: width; detector: performance; detector: upgrade; cosmic background radiation: B-mode; noise; gravitational radiation: primordial; bolometer; optics; [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det]; [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]; Austin; Austral; South Pole; South pole
• Online Access: https://hal.science/hal-01851180; https://doi.org/10.1117/12.2313854

International audience BICEP3 is a 520mm aperture on-axis refracting telescope observing the polarization of the cosmic microwave background (CMB) at 95GHz in search of the B-mode signal originating from in ationary gravitational waves. BICEP3's focal plane is populated with modularized tiles of antenna-coupled transition edge sensor (TES) bolometers. BICEP3 was deployed to the South Pole during 2014-15 austral summer and has been operational since. During the 2016-17 austral summer, we implemented changes to optical elements that lead to better noise performance. We discuss this upgrade and show the performance of BICEP3 at its full mapping speed from the 2017 and 2018 observing seasons. BICEP3 achieves an order-of-magnitude improvement in mapping speed compared to a Keck 95GHz receiver. We demonstrate 6.6μK√s noise performance of the BICEP3 receiver.