L-BASS: A project to produce an absolutely calibrated 1.4 GHz sky map. II -- Technical Description of the System

TL;DR

L-BASS is a specialized instrument designed to produce an accurately calibrated 1.4 GHz sky map by combining relative sky measurements with absolute calibration using a cryogenic load.

Contribution

This paper provides a detailed technical description of the L-BASS system and reports laboratory performance measurements of its components.

Findings

System design achieves high absolute calibration accuracy

Laboratory tests validate component performance

Method enables precise sky temperature measurements

Abstract

L-BASS is an instrument designed to make radiometric temperature measurements of the sky with an absolute accuracy of better than 0.1 K at 1.4 GHz. This will be achieved in two steps: first by measuring the sky temperature relative to that of the North Celestial Pole, using two horn-based antennas, and second with the sky antenna replaced with a calibrated cryogenic load to measure the absolute brightness temperature of the North Celesial Pole. Here we describe the design of the L-BASS two-antenna system and report on laboratory measurements to establish its performance at component and sub-system level.