New Cooled Feeds for the Allen Telescope Array

TL;DR

This paper introduces a new cooled broadband feed design for the Allen Telescope Array, significantly reducing noise temperatures across a wide frequency range to enhance radio astronomical observations.

Contribution

Development of a low noise, broadband feed system with cooling for the Allen Telescope Array, improving system temperature performance from 0.9 to 14 GHz.

Findings

Total system temperatures of 25-30 K from 1 to 5 GHz.

Total system temperatures of 40-50 K up to 12.5 GHz.

Feeds operate effectively over 0.9 to 14 GHz.

Abstract

We have developed a new generation of low noise, broadband feeds for the Allen Telescope Array at the Hat Creek Observatory in Northern California. The new feeds operate over the frequency range 0.9 to 14 GHz. The noise temperatures of the feeds have been substantially improved by cooling the entire feed structure as well as the low noise amplifiers to 70 K. To achieve this improved performance, the new feeds are mounted in glass vacuum bottles with plastic lenses that maximize the microwave transmission through the bottles. Both the cooled feeds and their low noise amplifiers produce total system temperatures that are in the range 25-30 K from 1 GHz to 5 GHz and 40-50 K up to 12.5 GHz.