CCAT: Nonlinear effects in 280 GHz aluminum kinetic inductance detectors

Abstract

Prime-Cam, a first-generation science instrument for the Atacama-based Fred Young Submillimeter Telescope, is being built by the CCAT Collaboration to observe at millimeter and submillimeter wavelengths using kinetic inductance detectors (KIDs). Prime-Cam's 280 GHz instrument module will deploy with two aluminum-based KID arrays and one titanium nitride-based KID array, totaling approximately 10,000 detectors at the focal plane, all of which have been fabricated and are currently undergoing testing. One complication of fielding large arrays of KIDs under dynamic loading conditions is tuning the detector tone powers to maximize signal-to-noise while avoiding bifurcation due to the nonlinear kinetic inductance. For aluminum-based KIDs, this is further complicated by additional nonlinear effects which couple tone power to resonator quality factors and resonant frequencies. While both nonequilibrium quasiparticle dynamics and two-level system fluctuations have been shown to give rise to qualitatively similar distortions, modeling these effects alongside nonlinear kinetic inductance is inefficient when fitting thousands of resonators on-sky with existing models. For this reason, it is necessary to have a detailed understanding of the nonlinear effects across relevant detector loading conditions, including how they impact on on-sky noise and how to diagnose the detector's relative performance. We present a study of the competing nonlinearities seen in Prime-Cam's 280 GHz aluminum KIDs, with a particular emphasis on the resulting distortions to the resonator line shape and how these impact detector parameter estimation.

arXiv comment10 pages, 4 figures, Conference proceedings from SPIE Astronomical Telescopes + Instrumentation (AS24)

References in corpus (16)

• A dual-band millimeter-wave kinetic inductance camera for the IRAM 30-meter telescope
• A semi-empirical model for two-level system noise in superconducting microresonators
• The NIKA2 large field-of-view millimeter continuum camera for the 30-m IRAM telescope
• Evidence of a nonequilibrium distribution of quasiparticles in the microwave response of a superconducting aluminium resonator
• Operation of a titanium nitride superconducting microresonator detector in the nonlinear regime
• CCAT-prime Collaboration: Science Goals and Forecasts with Prime-Cam on the Fred Young Submillimeter Telescope
• Quasiparticle generation efficiency in superconducting thin-films
• Coherent excited states in superconductors due to a microwave field
• Non-equilibrium superconductivity in superconducting resonators
• Sensitivity of the Prime-Cam Instrument on the CCAT-prime Telescope
• Nonlinear Effects in Superconducting Thin Film Microwave Resonators
• The non-equilibrium response of a superconductor to pair-breaking radiation measured over a broad frequency band
• Prime-Cam: A first-light instrument for the CCAT-prime telescope
• Electrothermal Model of Kinetic Inductance Detectors
• MUSCAT: The Mexico-UK Sub-Millimetre Camera for AsTronomy
• CCAT: Comparisons of 280 GHz TiN and Al Kinetic Inductance Detector Arrays