A kilo-pixel imaging system for future space based far-infrared observatories using microwave kinetic inductance detectors

A&A 601, A89 (2017) DOI: 10.1051/0004-6361/201629653 Astronomy & Astrophysics c ESO 2017 A kilo-pixel imaging system for future space based far-infrared observatories using microwave kinetic inductance detectors J. J. A. Baselmans1, 2 , J. Bueno1 , S. J. C. Yates3 , O. Yurduseven2 , N. Llombart2 , K. Karatsu2 , A. M. Baryshev3, 4 , L. Ferrari2 , A. Endo2, 5 , D. J. Thoen2 , P. J. de Visser1 , R. M. J. Janssen5, 6 , V. Murugesan1 , E. F. C. Driessen7 , G. Coiffard7 , J. Martin-Pintado8 , P. Hargrave9 , and M. Griffin9 . 1 SRON–Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands e-mail: 2 Terahertz Sensing Group, Delft University of Technology, Mekelweg 1, 2628 CD Delft, The Netherlands 3 SRON–Netherlands Institute for Space Research, Landleven 12, 9747AD Groningen, The Netherlands 4 Kapteyn Astronomical Institute, University of Groningen, Landleven 12, 9747 AD Groningen, The Netherlands 5 Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands 6 Leiden Observatory, University of Leiden, PO Box 9513, 2300 RA Leiden, The Netherlands 7 Institut de RadioAstronomie Millimétrique (IRAM), 300 rue de la Piscine, 38406 Saint-Martin-d’Hères (Grenoble), France 8 Centro de Astrobiologia, Ctra de Torrejón a Ajalvir, km 4, 28850 Torrejon de Ardoz (Madrid), Spain 9 Cardiff school of Physics and Astronomy, The Parade, Cardiff CF24 3AA, UK Received 5 September 2016 / Accepted 22 February 2017 ABSTRACT Aims. Future astrophysics and cosmic microwave background space missions operating in the far-infrared to millimetre part of the spectrum will require very large arrays of ultra-sensitive detectors in combination with high multiplexing factors and efficient lownoise and low-power readout systems. We have developed a demonstrator system suitable for such applications. Methods. The system combines a 961 pixel imaging array based upon Microwave Kinetic Inductance Detectors (MKIDs) with a readout system capable of reading out all pixels simultaneously with only one readout cable pair and a single cryogenic amplifier. We evaluate, in a representative environment, the system performance in terms of sensitivity, dynamic range, optical efficiency, cosmic ray rejection, pixel-pixel crosstalk and overall yield at an observation centre frequency of 850 GHz and 20% fractional√bandwidth. Results. The overall system has an excellent sensitivity, with an average detector sensitivity hNEPdet i = 3 × 10−19 W/ Hz measured using a thermal calibration source. At a loading power per pixel of 50 fW we demonstrate white, photon noise limited detector noise down to 300 mHz. The dynamic range would allow the detection of ∼1 Jy bright sources within the field of view without tuning the readout of the detectors. The expected dead time due to cosmic ray interactions, when operated in an L2 or a similar far-Earth orbit, is found to be <4%. Additionally, the achieved pixel yield is 83% and the crosstalk between the pixels is <−30 dB. Conclusions. This demonstrates that MKID technology can provide multiplexing ratios on the order of a 1000 with state-of-the-art single pixel performance, and that the technology is now mature enough to be considered for future space based observatories and experiments. Key words. instrumentation: detectors – techniques: miscellaneous 1. Introduction About half the energy generated in the Universe since the Big Bang, from stellar radiation and accretion processes, comes to us in the far infrared (FIR) and sub-mm spectral range (0.03–1 mm) (Dole et al. 2006). Access to this spectral range is therefore essential for astrophysics and cosmology as it allows us to gain understanding of cold, distant, and dust enshrouded objects, many of which are completely invisible in other spectral ranges. Unfortunately observations are very difficult: the Earth’s atmosphere is opaque over a large fraction of this spectral range, thus requiring observations from space. To reach the natural astrophysical backgrounds an observatory with an actively cooled telescope is required for a large fraction of the FIR spectral range in combination with background limited detectors. The required photon noise limited sensitivity of the detectors, NEPph , depends on the power absorbed per √pixel in the instrument and ranges from NEPph ∼ 5 × 10−18 W/ Hz for cosmic microwave background √ (CMB) instrument to NEPph ∼ 1 × 10−20 W/ Hz for a grating spectrometer on an observatory with a 5-K telescope. For most space missions the total pixel count needed will be ∼104 . The combination of sensitivity and pixel count presents a major challenge for future detector systems. Recent experiments using thermal calibration sources have shown that it is possible to reach, or at least approach, the required detector sensitivities with a number of different technologies. Examples are Quantum Capacitance Detectors (QCD’s; Echternach et al. 2013), Transition Edge Sensors (TES’s; Suzuki et al. 2016; Audley et al. 2016), small-volume hot-electron bolometers (Karasik & Cantor 2011) and Microwave Kinetic Inductance Detectors (MKIDs; de Visser et al. 2014). MKIDs, pioneered by Day et al. (2003), are in essence superconducting resonant circuits designed to Article published by EDP Sciences A89, page 1 of 16 A&A 601, A89 (2017) Table 1. Detector requirements for the various mission concepts discussed in the text. λ (µm) 25–50 50–100 100–200 200–400 30 60 120 240 400 30 60 120 240 400 Pdet (fW) 0.029 0.022 0.018 0.83 0.053 0.043 0.030 0.041 0.27 0.053 0.88 24 77 89 NEPph√ (10−19 W/ Hz) 6.1 3.7 2.4 10 8.5 5.2 3.3 2.6 5.2 8.5 24 89 113 93 Pdet for 1 Jy (fW) 4.6 2.3 1.2 0.58 30 15 7.4 3.7 2.2 120 60 30 15 8.9 Time constant (ms) 0.2 1/ f knee (Hz) 1 30 0.1 30 0.1 Single dish Grating spectrometer 3 m / 5 K telescope 0.5λ/D pixels λ/∆λ = 1000 30 60 120 240 400 9.1 × 10−5 7.1 × 10−5 5.2 × 10−5 6.9 × 10−5 4.8 × 10−5 0.35 0.22 0.13 0.11 0.22 0.052 0.026 0.013 0.0065 0.039 100 0.1 Single dish Grating spectrometer 10 m / 25 K telescope 0.5λ/D pixels λ/∆λ = 1000 30 60 120 240 400 400 600 900 1400 2000 3000 9.1 × 10−5 1.5 × 10−4 0.044 0.13 0.15 120 110 96 107 123 129 0.35 1.0 3.3 2.6 5.2 111 85 65 54 50 41 0.21 0.1 0.052 0.026 0.016 0.57 0.38 0.25 0.16 0.11 0.076 100 0.1 5 0.1 Double Fourier interferometer 2 3 m / 5 K telescopes 0.5λ/D pixels Single dish Broadband camera 3 m / 5 K telescope 0.5λ/D pixels λ/∆λ = 3 Single dish Broadband camera 10 m / 25 K telescope 0.5λ/D pixels λ/∆λ = 3 CMB experiment 2 m / 30 K telescope 1λ/D pixels λ/∆λ = 3 Notes. On top of the requirements listed in the table, all detector systems have the common requirements of: i) a cosmic ray dead time <20% and ii) a pixel-pixel crosstalk (after data de-correlation) <−30 dB. Additionally all instruments will require on the order of several 104 of pixels. efficiently absorb radiation. They offer an attractive option to construct a la (...truncated)