BICEP2 and Keck array: Upgrades and improved beam characterization

I. Buder; P. A R Ade; Z. Ahmed; R. W. Aikin; K. D. Alexander; M. Amiri; D. Barkats; S. J. Benton; C. A. Bischoff; J. J. Bock; J. A. Bonetti; J. A. Brevik; E. Bullock; B. Burger; B. P. Crill; G. Davis; C. D. Dowell; L. Duband; J. P. Filippini; S. Fliescher; S. R. Golwala; M. S. Gordon; M. Halpern; M. Hasselfield; S. R. Hildebrandt; G. C. Hilton; V. V. Hristov; H. Hui; K. D. Irwin; K. S. Karkare; J. P. Kaufman; B. G. Keating; S. Kefeli; S. A. Kernasovskiy; J. M. Kovac; C. L. Kuo; E. M. Leitch; M. Lueker; P. Mason; K. G. Megerian; C. B. Netterfield; H. T. Nguyen; R. O'Brient; R. W. Ogburn; A. Orlando; C. Pryke; C. D. Reintsema; S. Richter; R. Schwarz; C. D. Sheehy; Z. K. Staniszewski; R. V. Sudiwala; G. P. Teply; K. L. Thompson; J. E. Tolan; A. D. Turner; A. G. Vieregg; A. C. Weber; D. V. Wiebe; P. Wilson; C. L. Wong; K. W. Yoon

doi:10.1117/12.2055713

BICEP2 and Keck array: Upgrades and improved beam characterization

I. Buder, P. A R Ade, Z. Ahmed, R. W. Aikin, K. D. Alexander, M. Amiri, D. Barkats, S. J. Benton, C. A. Bischoff, J. J. Bock, J. A. Bonetti, J. A. Brevik, E. Bullock, B. Burger, B. P. Crill, G. Davis, C. D. Dowell, L. Duband, J. P. Filippini, S. FliescherS. R. Golwala, M. S. Gordon, M. Halpern, M. Hasselfield, S. R. Hildebrandt, G. C. Hilton, V. V. Hristov, H. Hui, K. D. Irwin, K. S. Karkare, J. P. Kaufman, B. G. Keating, S. Kefeli, S. A. Kernasovskiy, J. M. Kovac, C. L. Kuo, E. M. Leitch, M. Lueker, P. Mason, K. G. Megerian, C. B. Netterfield, H. T. Nguyen, R. O'Brient, R. W. Ogburn, A. Orlando, C. Pryke, C. D. Reintsema, S. Richter, R. Schwarz, C. D. Sheehy, Z. K. Staniszewski, R. V. Sudiwala, G. P. Teply, K. L. Thompson, J. E. Tolan, A. D. Turner, A. G. Vieregg, A. C. Weber, D. V. Wiebe, P. Wilson, C. L. Wong, K. W. Yoon

Physics and Astronomy (Twin Cities)

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

19 Scopus citations

Abstract

Searching for evidence of inflation by measuring B-modes in the cosmic microwave background (CMB) polarization at degree angular scales remains one of the most compelling experimental challenges in cosmology. BICEP2 and the Keck Array are part of a program of experiments at the South Pole whose main goal is to achieve the sensitivity and systematic control necessary for measurements of the tensor-to-scalar ratio at σ(r) ∼0:01. Beam imperfections that are not sufficiently accounted for are a potential source of spurious polarization that could interfere with that goal. The strategy of BICEP2 and the Keck Array is to completely characterize their telescopes' polarized beam response with a combination of in-lab, pre-deployment, and on-site calibrations. We Sereport the status of these experiments, focusing on continued improved understanding of their beams. Far-field measurements of the BICEP2 beam with a chopped thermal source, combined with analysis improvements, show that the level of residual beam-induced systematic errors is acceptable for the goal of σ(r) ∼ 0:01 measurements. Beam measurements of the Keck Array side lobes helped identify a way to reduce optical loading with interior cold baffles, which we installed in late 2013. These baffles reduced total optical loading, leading to a ∼ 10% increase in mapping speed for the 2014 observing season. The sensitivity of the Keck Array continues to improve: for the 2013 season it was 9:5 μ 1/4K s noise equivalent temperature (NET). In 2014 we converted two of the 150-GHz cameras to 100 GHz for foreground separation capability. We have shown that the BICEP2 and the Keck Array telescope technology is sufficient for the goal of σ(r) ∼ 0:01 measurements. Furthermore, the program is continuing with BICEP3, a 100-GHz telescope with 2560 detectors.

Original language	English (US)
Title of host publication	Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII
Editors	Jonas Zmuidzinas, Wayne S. Holland
Publisher	SPIE
ISBN (Electronic)	9780819496218
DOIs	https://doi.org/10.1117/12.2055713
State	Published - 2014
Event	Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII - Montreal, Canada Duration: Jun 24 2014 → Jun 27 2014

Publication series

Name	Proceedings of SPIE - The International Society for Optical Engineering
Volume	9153
ISSN (Print)	0277-786X
ISSN (Electronic)	1996-756X

Other

Other	Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII
Country/Territory	Canada
City	Montreal
Period	6/24/14 → 6/27/14

Bibliographical note

Publisher Copyright:
© 2014 SPIE.

Keywords

BICEP2
Cosmic microwave background
Gravitational waves
Ination
Keck Array.
polarization

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10.1117/12.2055713

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Buder, I., Ade, P. A. R., Ahmed, Z., Aikin, R. W., Alexander, K. D., Amiri, M., Barkats, D., Benton, S. J., Bischoff, C. A., Bock, J. J., Bonetti, J. A., Brevik, J. A., Bullock, E., Burger, B., Crill, B. P., Davis, G., Dowell, C. D., Duband, L., Filippini, J. P., ... Yoon, K. W. (2014). BICEP2 and Keck array: Upgrades and improved beam characterization. In J. Zmuidzinas, & W. S. Holland (Eds.), Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII Article 915312 (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 9153). SPIE. https://doi.org/10.1117/12.2055713

BICEP2 and Keck array: Upgrades and improved beam characterization. / Buder, I.; Ade, P. A R; Ahmed, Z. et al.
Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII. ed. / Jonas Zmuidzinas; Wayne S. Holland. SPIE, 2014. 915312 (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 9153).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

Buder, I, Ade, PAR, Ahmed, Z, Aikin, RW, Alexander, KD, Amiri, M, Barkats, D, Benton, SJ, Bischoff, CA, Bock, JJ, Bonetti, JA, Brevik, JA, Bullock, E, Burger, B, Crill, BP, Davis, G, Dowell, CD, Duband, L, Filippini, JP, Fliescher, S, Golwala, SR, Gordon, MS, Halpern, M, Hasselfield, M, Hildebrandt, SR, Hilton, GC, Hristov, VV, Hui, H, Irwin, KD, Karkare, KS, Kaufman, JP, Keating, BG, Kefeli, S, Kernasovskiy, SA, Kovac, JM, Kuo, CL, Leitch, EM, Lueker, M, Mason, P, Megerian, KG, Netterfield, CB, Nguyen, HT, O'Brient, R, Ogburn, RW, Orlando, A, Pryke, C, Reintsema, CD, Richter, S, Schwarz, R, Sheehy, CD, Staniszewski, ZK, Sudiwala, RV, Teply, GP, Thompson, KL, Tolan, JE, Turner, AD, Vieregg, AG, Weber, AC, Wiebe, DV, Wilson, P, Wong, CL & Yoon, KW 2014, BICEP2 and Keck array: Upgrades and improved beam characterization. in J Zmuidzinas & WS Holland (eds), Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII., 915312, Proceedings of SPIE - The International Society for Optical Engineering, vol. 9153, SPIE, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII, Montreal, Canada, 6/24/14. https://doi.org/10.1117/12.2055713

Buder I, Ade PAR, Ahmed Z, Aikin RW, Alexander KD, Amiri M et al. BICEP2 and Keck array: Upgrades and improved beam characterization. In Zmuidzinas J, Holland WS, editors, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII. SPIE. 2014. 915312. (Proceedings of SPIE - The International Society for Optical Engineering). doi: 10.1117/12.2055713

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abstract = "Searching for evidence of inflation by measuring B-modes in the cosmic microwave background (CMB) polarization at degree angular scales remains one of the most compelling experimental challenges in cosmology. BICEP2 and the Keck Array are part of a program of experiments at the South Pole whose main goal is to achieve the sensitivity and systematic control necessary for measurements of the tensor-to-scalar ratio at σ(r) ∼0:01. Beam imperfections that are not sufficiently accounted for are a potential source of spurious polarization that could interfere with that goal. The strategy of BICEP2 and the Keck Array is to completely characterize their telescopes' polarized beam response with a combination of in-lab, pre-deployment, and on-site calibrations. We Sereport the status of these experiments, focusing on continued improved understanding of their beams. Far-field measurements of the BICEP2 beam with a chopped thermal source, combined with analysis improvements, show that the level of residual beam-induced systematic errors is acceptable for the goal of σ(r) ∼ 0:01 measurements. Beam measurements of the Keck Array side lobes helped identify a way to reduce optical loading with interior cold baffles, which we installed in late 2013. These baffles reduced total optical loading, leading to a ∼ 10% increase in mapping speed for the 2014 observing season. The sensitivity of the Keck Array continues to improve: for the 2013 season it was 9:5 μ 1/4K s noise equivalent temperature (NET). In 2014 we converted two of the 150-GHz cameras to 100 GHz for foreground separation capability. We have shown that the BICEP2 and the Keck Array telescope technology is sufficient for the goal of σ(r) ∼ 0:01 measurements. Furthermore, the program is continuing with BICEP3, a 100-GHz telescope with 2560 detectors.",

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note = "Publisher Copyright: {\textcopyright} 2014 SPIE.; Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII ; Conference date: 24-06-2014 Through 27-06-2014",

year = "2014",

doi = "10.1117/12.2055713",

language = "English (US)",

series = "Proceedings of SPIE - The International Society for Optical Engineering",

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editor = "Jonas Zmuidzinas and Holland, {Wayne S.}",

booktitle = "Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII",

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T2 - Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII

AU - Buder, I.

AU - Ade, P. A R

AU - Ahmed, Z.

AU - Aikin, R. W.

AU - Alexander, K. D.

AU - Amiri, M.

AU - Barkats, D.

AU - Benton, S. J.

AU - Bischoff, C. A.

AU - Bock, J. J.

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AU - Filippini, J. P.

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AU - Hasselfield, M.

AU - Hildebrandt, S. R.

AU - Hilton, G. C.

AU - Hristov, V. V.

AU - Hui, H.

AU - Irwin, K. D.

AU - Karkare, K. S.

AU - Kaufman, J. P.

AU - Keating, B. G.

AU - Kefeli, S.

AU - Kernasovskiy, S. A.

AU - Kovac, J. M.

AU - Kuo, C. L.

AU - Leitch, E. M.

AU - Lueker, M.

AU - Mason, P.

AU - Megerian, K. G.

AU - Netterfield, C. B.

AU - Nguyen, H. T.

AU - O'Brient, R.

AU - Ogburn, R. W.

AU - Orlando, A.

AU - Pryke, C.

AU - Reintsema, C. D.

AU - Richter, S.

AU - Schwarz, R.

AU - Sheehy, C. D.

AU - Staniszewski, Z. K.

AU - Sudiwala, R. V.

AU - Teply, G. P.

AU - Thompson, K. L.

AU - Tolan, J. E.

AU - Turner, A. D.

AU - Vieregg, A. G.

AU - Weber, A. C.

AU - Wiebe, D. V.

AU - Wilson, P.

AU - Wong, C. L.

AU - Yoon, K. W.

PY - 2014

Y1 - 2014

N2 - Searching for evidence of inflation by measuring B-modes in the cosmic microwave background (CMB) polarization at degree angular scales remains one of the most compelling experimental challenges in cosmology. BICEP2 and the Keck Array are part of a program of experiments at the South Pole whose main goal is to achieve the sensitivity and systematic control necessary for measurements of the tensor-to-scalar ratio at σ(r) ∼0:01. Beam imperfections that are not sufficiently accounted for are a potential source of spurious polarization that could interfere with that goal. The strategy of BICEP2 and the Keck Array is to completely characterize their telescopes' polarized beam response with a combination of in-lab, pre-deployment, and on-site calibrations. We Sereport the status of these experiments, focusing on continued improved understanding of their beams. Far-field measurements of the BICEP2 beam with a chopped thermal source, combined with analysis improvements, show that the level of residual beam-induced systematic errors is acceptable for the goal of σ(r) ∼ 0:01 measurements. Beam measurements of the Keck Array side lobes helped identify a way to reduce optical loading with interior cold baffles, which we installed in late 2013. These baffles reduced total optical loading, leading to a ∼ 10% increase in mapping speed for the 2014 observing season. The sensitivity of the Keck Array continues to improve: for the 2013 season it was 9:5 μ 1/4K s noise equivalent temperature (NET). In 2014 we converted two of the 150-GHz cameras to 100 GHz for foreground separation capability. We have shown that the BICEP2 and the Keck Array telescope technology is sufficient for the goal of σ(r) ∼ 0:01 measurements. Furthermore, the program is continuing with BICEP3, a 100-GHz telescope with 2560 detectors.

AB - Searching for evidence of inflation by measuring B-modes in the cosmic microwave background (CMB) polarization at degree angular scales remains one of the most compelling experimental challenges in cosmology. BICEP2 and the Keck Array are part of a program of experiments at the South Pole whose main goal is to achieve the sensitivity and systematic control necessary for measurements of the tensor-to-scalar ratio at σ(r) ∼0:01. Beam imperfections that are not sufficiently accounted for are a potential source of spurious polarization that could interfere with that goal. The strategy of BICEP2 and the Keck Array is to completely characterize their telescopes' polarized beam response with a combination of in-lab, pre-deployment, and on-site calibrations. We Sereport the status of these experiments, focusing on continued improved understanding of their beams. Far-field measurements of the BICEP2 beam with a chopped thermal source, combined with analysis improvements, show that the level of residual beam-induced systematic errors is acceptable for the goal of σ(r) ∼ 0:01 measurements. Beam measurements of the Keck Array side lobes helped identify a way to reduce optical loading with interior cold baffles, which we installed in late 2013. These baffles reduced total optical loading, leading to a ∼ 10% increase in mapping speed for the 2014 observing season. The sensitivity of the Keck Array continues to improve: for the 2013 season it was 9:5 μ 1/4K s noise equivalent temperature (NET). In 2014 we converted two of the 150-GHz cameras to 100 GHz for foreground separation capability. We have shown that the BICEP2 and the Keck Array telescope technology is sufficient for the goal of σ(r) ∼ 0:01 measurements. Furthermore, the program is continuing with BICEP3, a 100-GHz telescope with 2560 detectors.

KW - BICEP2

KW - Cosmic microwave background

KW - Gravitational waves

KW - Ination

KW - Keck Array.

KW - polarization

UR - http://www.scopus.com/inward/record.url?scp=84922901072&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84922901072&partnerID=8YFLogxK

U2 - 10.1117/12.2055713

DO - 10.1117/12.2055713

M3 - Conference contribution

AN - SCOPUS:84922901072

T3 - Proceedings of SPIE - The International Society for Optical Engineering

BT - Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VII

A2 - Zmuidzinas, Jonas

A2 - Holland, Wayne S.

PB - SPIE

Y2 - 24 June 2014 through 27 June 2014

ER -

BICEP2 and Keck array: Upgrades and improved beam characterization

Abstract

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