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

¹ SRON–Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
e-mail: J.Baselmans@sron.nl
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 low-noise 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 $\mathrm{⟨}\mathrm{NE}{\mathrm{P}}_{\det }\mathrm{⟩}\mathrm{=}\mathrm{3}\mathrm{\times }{\mathrm{10}}^{-19}\mathrm{W}\mathit{/}\sqrt{\mathrm{Hz}}$ 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.