Design and Assembly of SPT-3G Cold Readout Hardware

J. S. Avva, P. A.R. Ade, Z. Ahmed, A. J. Anderson, J. E. Austermann, R. Basu Thakur, D. Barron, A. N. Bender, B. A. Benson, J. E. Carlstrom, F. W. Carter, T. Cecil, C. L. Chang, J. F. Cliche, A. Cukierman, E. V. Denison, T. de Haan, J. Ding, M. A. Dobbs, D. DutcherT. Elleflot, W. Everett, A. Foster, R. N. Gannon, A. Gilbert, J. C. Groh, N. W. Halverson, A. H. Harke-Hosemann, N. L. Harrington, M. Hasegawa, K. Hattori, J. W. Henning, G. C. Hilton, W. L. Holzapfel, Y. Hori, N. Huang, K. D. Irwin, O. B. Jeong, M. Jonas, T. Khaire, A. M. Kofman, M. Korman, D. Kubik, S. Kuhlmann, C. L. Kuo, A. T. Lee, A. E. Lowitz, S. S. Meyer, J. Montgomery, A. Nadolski, T. Natoli, H. Nguyen, H. Nishino, G. I. Noble, V. Novosad, S. Padin, Z. Pan, J. Pearson, C. M. Posada, A. Rahlin, K. Rotermund, J. E. Ruhl, L. J. Saunders, J. T. Sayre, I. Shirley, E. Shirokoff, G. Smecher, J. A. Sobrin, A. A. Stark, K. T. Story, A. Suzuki, Q. Y. Tang, K. L. Thompson, C. Tucker, L. R. Vale, K. Vanderlinde, J. D. Vieira, G. Wang, N. Whitehorn, V. Yefremenko, K. W. Yoon, M. R. Young

Research output: Contribution to journalArticlepeer-review


The third-generation upgrade to the receiver on the South Pole Telescope, SPT-3G, was installed at the South Pole during the 2016–2017 austral summer to measure the polarization of the cosmic microwave background. Increasing the number of detectors by a factor of 10 to ∼ 16 , 000 required the multiplexing factor to increase to 68 and the bandwidth of the frequency-division readout electronics to span 1.6–5.2 MHz. This increase necessitates low-thermal conductance, low-inductance cryogenic wiring. Our cold readout system consists of planar thin-film aluminum inductive–capacitive resonators, wired in series with the detectors, summed together, and connected to 4K SQUIDs by 10 - μ m -thick niobium–titanium (NbTi) broadside-coupled striplines. Here, we present an overview of the cold readout electronics for SPT-3G, including assembly details and characterization of electrical and thermal properties of the system. We report, for the NbTi striplines, values of R≤ 10 - 4Ω , L=21±1nH, and C=1.47±.02nF. Additionally, the striplines’ thermal conductivity is described by kA=6.0±0.3T0.92±0.04μWmmK-1. Finally, we provide projections for cross talk induced by parasitic impedances from the stripline and find that the median value of percentage cross talk from leakage current is 0.22 and 0.09 % from wiring impedance.

Original languageEnglish (US)
Pages (from-to)547-555
Number of pages9
JournalJournal of Low Temperature Physics
Issue number3-4
StatePublished - Nov 1 2018


  • Cosmic microwave background
  • Frequency-division multiplexing
  • SPT-3G

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Condensed Matter Physics


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