Receiver design for the REACH global 21-cm signal experiment

Abstract

We detail the the REACH radiometric system designed to enable measurements of the 21-cm neutral hydrogen line. Included is the radiometer architecture and end-to-end system simulations as well as a discussion of the challenges intrinsic to highly-calibratable system development. Following this, we share laboratory results based on the calculation of noise wave parameters utilising an over-constrained least squares approach demonstrating a calibration RMSE of 80 mK for five hours of integration on a custom-made source with comparable impedance to that of the antenna used in the field. This paper therefore documents the state of the calibrator and data analysis in December 2022 in Cambridge before shipping to South Africa.

30 pages, 19 figures

References in corpus (5)

• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• The REACH radiometer for detecting the 21-cm hydrogen signal from redshift 7.5 to 28
• SARAS measurement of the Radio Background at long wavelengths
• Antenna beam characterisation for the global 21cm experiment LEDA and its impact on signal model parameter reconstruction
• Bayesian approach to radio frequency interference mitigation

Cited by in corpus (6)

• RHINO: A large horn antenna for detecting the 21cm global signal
• A Bayesian approach to modelling spectrometer data chromaticity corrected using beam factors -- II. Model priors and posterior odds
• Accounting for Noise and Singularities in Bayesian Calibration Methods for Global 21-cm Cosmology Experiments
• Radiometer Calibration using Machine Learning
• The magnitude of the dark ages 21-cm signal in the context of existing early and late time constraints on $\Lambda$CDM
• Capturing System Drift with Time Series Calibration for Global 21-cm Cosmology Experiments