A new technique to measure noise parameters for global 21-cm experiments

TL;DR

This paper presents a practical method for accurately measuring noise parameters in radiometer systems, crucial for calibrating low-frequency receivers in global 21-cm experiments targeting the Cosmic Dawn and Epoch of Reionization.

Contribution

It introduces a new, practical technique for measuring receiver noise parameters, improving calibration accuracy for 21-cm cosmology experiments.

Findings

The method effectively measures noise parameters in low-frequency radiometers.

It simplifies calibration procedures for global 21-cm experiments.

The technique enhances the precision of cosmological signal detection.

Abstract

Radiometer experiments to detect 21-cm Hydrogen line emission from the Cosmic Dawn and Epoch of Reionization rely upon precise absolute calibration. During calibration, noise generated by amplifiers within the radiometer receiver must be accounted for; however, it is difficult to measure as the noise power varies with source impedance. In this letter, we introduce a convenient method to measure the noise parameters of a receiver system, which is practical for low-frequency receivers used in global 21-cm experiments.