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Updated: Jun 1, 2025
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Continuous-Wave Propagation Channel-Sounding Measurement System - Testing, Verification, and Measurements
Published on: June 25, 2021
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Receiver design for the REACH global 21-cm signal experiment
Ian L V Roque1,2, Nima Razavi-Ghods1, Steven H Carey1
1Cavendish Astrophysics, University of Cambridge, Cambridge, UK.
Experimental Astronomy
|January 21, 2025
Summary
The REACH radiometric system enables 21-cm neutral hydrogen line measurements. Laboratory results show an 80 mK calibration Root Mean Square Error (RMSE) using noise wave parameters.
Area of Science:
- Radio astronomy
- Cosmic microwave background radiation
- Astrophysical cosmology
Background:
- The 21-cm neutral hydrogen line is a crucial probe of the early universe.
- Developing highly-calibratable radiometric systems presents significant technical challenges.
Purpose of the Study:
- To detail the REACH radiometric system for 21-cm line measurements.
- To present laboratory results validating the system's calibration accuracy.
Main Methods:
- Radiometer architecture and end-to-end system simulations.
- Calculation of noise wave parameters using an over-constrained least squares approach.
- Laboratory calibration using a custom-made source.
Main Results:
- Demonstrated a calibration Root Mean Square Error (RMSE) of 80 mK.
- Achieved this result after five hours of integration on a custom source.
- Detailed the calibrator and data analysis state as of December 2022.
Conclusions:
- The REACH system is a promising tool for precise 21-cm line measurements.
- The laboratory results validate the system's high degree of calibration.
- The system is ready for deployment in South Africa for field measurements.
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