Advanced ACTPol is a polarization-sensitive upgrade for the 6 m aperture Atacama Cosmology Telescope, adding new frequencies and increasing sensitivity over the previous ACTPol receiver. In 2016, Advanced ACTPol will begin to map approximately half the sky in five frequency bands (28–230 GHz). Its maps of primary and secondary cosmic microwave background anisotropies—imaged in intensity and polarization at few arcminute-scale resolution—will enable precision cosmological constraints and also a wide array of cross-correlation science that probes the expansion history of the universe and the growth of structure via gravitational collapse. To accomplish these scientific goals, the Advanced ACTPol receiver will be a significant upgrade to the ACTPol receiver, including four new multichroic arrays of cryogenic, feedhorn-coupled AlMn transition edge sensor polarimeters (fabricated on 150 mm diameter wafers); a system of continuously rotating meta-material silicon half-wave plates; and a new multiplexing readout architecture which uses superconducting quantum interference devices and time division to achieve a 64-row multiplexing factor. Here we present the status and scientific goals of the Advanced ACTPol instrument, emphasizing the design and implementation of the Advanced ACTPol cryogenic detector arrays.

This work was supported by the U.S. National Science Foundation through Awards 1312380 and 1440226. The NIST authors would like to acknowledge the support of the NIST Quantum Initiative. The development of multichroic detectors and lenses was supported by NASA Grants NNX13AE56G and NNX14AB58G. The work of KPC, KTC, EG, BJK, CM, BLS, JTW, and SMS was supported by NASA Space Technology Research Fellowship awards.

Authors and Affiliations

1. Department of Physics, Cornell University, Ithaca, NY, 14853, USA

   S. W. Henderson, F. De Bernardis, P. A. Gallardo, B. J. Koopman, M. D. Niemack, J. R. Stevens & E. M. Vavagiakis

2. Sub-Department of Astrophysics, University of Oxford, Keble Road, Oxford, OX1 3RH, UK

   R. Allison & J. Dunkley

3. NIST Quantum Devices Group, 325 Broadway Mailcode 817.03, Boulder, CO, 80305, USA

   J. Austermann, J. A. Beall, D. Becker, S. M. Duff, G. C. Hilton, J. Hubmayr, D. Li & J. Van Lanen

4. Department of Physics, University of Michigan, Ann Arbor, 48103, USA

   T. Baildon, K. P. Coughlin, R. Datta, F. Hills, J. McMahon & C. Munson

5. Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ, 08544, USA

   N. Battaglia, E. Calabrese, M. Hasselfield, R. Hloẑek & D. N. Spergel

6. Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON, M5S 3H8, Canada

   J. R. Bond & A. van Engelen

7. Joseph Henry Laboratories of Physics, Jadwin Hall, Princeton University, Princeton, NJ, 08544, USA

   S. K. Choi, K. T. Crowley, E. Grace, S. P. Ho, P. Niraula, L. A. Page, C. G. Pappas, M. Salatino, A. Schillaci, S. M. Simon & S. T. Staggs

8. Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA, 19104, USA

   M. J. Devlin, F. Nati, B. L. Schmitt & J. T. Ward

9. Departamento de Astronomía y Astrofísica, Ponticía Universidad Católica, Casilla 306, Santiago 22, Chile

   R. Dünner

10. Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada

    A. D. Hincks

11. Department of Physics, Florida State University, Tallahassee, FL, 32306, USA

    K. Huffenberger

12. Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854-8019, USA

    J. P. Hughes

13. Department of Physics, Stanford University, Stanford, CA, 94305-4085, USA

    K. D. Irwin

14. Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA, 15260, USA

    A. B. Kosowsky

15. SLAC National Accelerator Laboratory, 2575 Sandy Hill Road, Menlo Park, CA, 94025, USA

    D. Li

16. Dunlap Institute, University of Toronto, 50 St. George St., Toronto, ON, M5S 3H4, Canada

    L. Newburgh

17. Physics and Astronomy Department, Stony Brook University, Stony Brook, NY, 11794, USA

    N. Sehgal

18. Berkeley Center for Cosmological Physics, University of California, Berkeley, CA, 94720, USA

    B. D. Sherwin

19. Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Durban, 4041, South Africa

    J. L. Sievers

20. Department of Physics, West Chester University of Pennsylvania, West Chester, PA, 19383, USA

    R. Thornton

21. NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA

    E. J. Wollack

22. Sociedad Radiosky Asesorías de Ingeniería Limitada Lincoyán 54, Depto 805, Concepción, Chile

    A. Schillaci

Corresponding author

Correspondence toS. W. Henderson.

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