Heterodyne Array Receivers for Space and Ground Based Applications

The first heterodyne array receivers have been successfully built for ground-based telescopes and airborne observatories. In the talk we give a very quick overview of some prior heterodyne arrays. In particular, we will look at the innovations they introduced and how these could be applied to future large (100 to 1000 pixel) arrays or space missions. Then we will present the first detailed design for a space application, the Heterodyne Receiver for the Origins Space Telescope (HERO). HERO follows the traditional design, but limited cooling power and the limited electrical power of the satellite pose major challenges. Minor challenges are limited availability of space and weight. For the eight 3x3 pixel arrays of which 4 can operate simultaneously we attributed 20mW at 4.5K, 35mW at 35K and 205 W at the satellite temperature. Therefore we propose to use SiGe cryogenic low noise amplifiers, with a dissipation of about 0.5mW for 6 GHz bandwidth. The power of the backends also needs to be reduced drastically to about 1 W for 6 GHz bandwidth. CMOS ASIC backends are one option, ADC, followed by FFTs and ACCs another. To reduce the volume and mass, we propose the cover the RF bandwidth of 486 GHz to 2700 GHz in only 4 bands, each with about 50% relative width.The design might not only be a helpful starting point for any heterodyne array on a satellite, but the low heat and power consumption might be also an essential first step for large (100 to 1000 pixels) heterodyne arrays for ground based telescopes or simply a more energy efficient alternative for any ALMA single pixel or array receiver

Origins Space Telescope: HEterodyne Receiver for OST (HERO)

The Origins Space Telescope (OST) is a mission concept for the Far-Infrared Surveyor, one of the four science and technology definition studies selected by NASA HQ for the 2020 Astronomy and Astrophysics Decadal survey. The OST study will encompass two mission concepts (poster by A. Cooray). Concept 1 is an extremely versatile observatory with 5 science instruments, of which the HEterodyne Receivers for OST (HERO) is one.HERO’s main targets are high spectral resolution observations (Dl/l up to 107 or Dv = 0.03km/s) of water to follow its trail from cores to YSOs as well as H2O and HDO observations on comets to explore the origins of water. HERO will probe all neutral ISM phases using cooling lines ([CII], [OI]) and hydrides as probes of CO-dark H2 (CH, HF). HERO will reveal how molecular clouds and filaments form in the local ISM up to nearby galaxies. HERO will enable detailed understanding of feedback mechanisms : shocks, cosmic rays, UV induced feedback and will provide a map of the cosmic ray ionization rate in the Galaxy and nearby galaxies using molecular ions (ArH+, OH+, H3O+).In order to achieve these observational goals, HERO will cover an extremely wide frequency range from 468 to 2700 GHz (641 to 111microns) and a window around the OI line at 4563 to 4752GHz (66 to 63 microns). It will consist of very large focal plane arrays of 128 pixels between 900 - 2700 GHz and at 4.7 THz, and 32 pixels for the 468 to 900 GHz range. The instrument is exploiting Herschel/HIFI heritage, but will go well beyond HIFIs capacities. HERO’s large arrays require low dissipation and low power components. The HERO concept makes use of the latest cryogenic SiGe amplifier technology, as well as CMOS technology for the backends with 2 orders of magnitude lower power. Advances in Local Oscillator technology have also been taken into account and ambitious, but realistic assumptions have been made for future amplifier multiplier chains going up to 4.7 THz.Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s. We welcome you to contact the Science and Technology Definition Team (STDT) with your science needs and ideas by emailing us at [email protected]