AMKID: A large KID-based camera at the APEX telescope

¹ Max Planck Institute für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
² SRON Netherlands Institute for Space Research, Landleven 12, 9747 AD Groningen, The Netherlands
³ Kapteyn Astronomical Institute, University of Groningen, Groningen, The Netherlands
⁴ Pontificia Universidad Catolica de Chile, San Joaquin, Chile
⁵ SRON Netherlands Institute for Space Research, Niels Bohrweg 4, 2333 CA Leiden, The Netherlands
⁶ Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands
⁷ I.Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, 50937 Cologne, Germany
⁸ Center for Astrophysics | Harvard & Smithsonian, 60 Garden St, Cambridge, MA 02138, USA

^★ Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 16 December 2025
Accepted: 3 February 2026

Abstract

Thermal emission at submillimeter wavelengths carries unique information for many astronomical applications, ranging from disks and planet formation around young stars to galaxy evolution studies at cosmological distances. Advancing the mapping speed to detect this faint emission in ground-based astronomy has been a technical challenge for decades. The APEX Microwave Kinetic Inductance Detector (AMKID) camera was designed to accomplish this task. The instrument is a wide field-of-view camera based on kinetic inductance detectors. It is installed on the 12-meter APEX telescope in Chile at 5100 meters above sea level. The instrument operates in dual color, covering the 350 and 850 GHz atmospheric windows simultaneously. It has a large field of view of 15.3′ × 15.3′ and an unprecedented number of pixels: 13 952 detectors in the high-frequency band and 3520 detectors in the low-frequency band. Here we present a complete description of the instrument design and construction, together with results from the successful low-frequency-array (LFA) commissioning campaign executed over the last year. The LFA performance is in good agreement with design parameters, with detector sensitivity of 2.2 mK s and diffraction-limited beam sizes of 17.0″. On-sky measurements demonstrate a sensitivity of 70–90 mJy s per detector under good atmospheric conditions (PWV below 1.0 mm). With this performance the LFA regularly achieves a mapping sensitivity of 25 mJy when mapping a square degree in one hour. AMKID on APEX with its dual-color observing capabilities, high sensitivity, large field of view, and high angular resolution promises to open new scientific opportunities with the APEX telescope.