Low-Temperature Noise Performance of SuperSpec and Other Developments on the Path to Deployment

R. McGeehan, P. S. Barry, E. Shirokoff, C. M. Bradford, G. Che, J. Glenn, S. Gordon, S. Hailey-Dunsheath, M. Hollister, A. Kovács, H. G. LeDuc, Philip Mauskopf, C. McKenney, T. Reck, J. Redford, C. Tucker, J. Turner, S. Walker, J. Wheeler, J. Zmuidzinas

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


SuperSpec is a compact on-chip spectrometer operating at mm and sub-mm wavelengths which will enable the construction of sensitive multibeam spectrometers. SuperSpec employs a filter bank architecture, consisting of lithographically patterned niobium superconducting microstrip mm-wave resonators. The power admitted by each resonator is detected by a titanium nitride lumped-element kinetic inductance detector (KID) with resonant frequency from 100 to 200 MHz. We present a characterization of the detector noise performance down to 10 mK measured in a dark setting. We report a device NEP of 2.7×10-18WHz-1/2 at 210 mK, which is below the expected photon noise level at high-altitude ground-based observatories. The NEP decreases to a constant value of approximately 7.0×10-19WHz-1/2 below 130 mK. The white noise is well modeled by thermal generation–recombination noise (GR noise) down to 130 mK and a noise floor at low temperatures. Moreover, the addition of low-pass coaxial filters further reduces the noise floor to achieve an NEP of 5.7×10-19WHz-1/2 below 100 mK. We discuss a photolithographic technique to adjust KID resonances that results in an f0 designed versus measured scatter of 1.7 × 10 - 5, which will allow a significant reduction in resonators lost to clashes in full-scale designs. Finally, we present a demonstration of a new ROACH-2-based readout system operating below 500 MHz and show preliminary data indicating the suitability of this system for future highly multiplexed KID arrays.

Original languageEnglish (US)
Pages (from-to)1024-1032
Number of pages9
JournalJournal of Low Temperature Physics
Issue number5-6
StatePublished - Dec 1 2018


  • Kinetic inductance detector
  • NEP
  • ROACH-2
  • Spectrometer
  • SuperSpec
  • TiN

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • General Materials Science
  • Condensed Matter Physics


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