Water vapour radiometers for the Australia telescope compact array

Balthasar T. Indermuehle; Michael G. Burton; Jonathan Crofts

doi:10.1117/12.925250

24 September 2012 Water vapour radiometers for the Australia telescope compact array

Balthasar T. Indermuehle, Michael G. Burton, Jonathan Crofts

Proceedings Volume 8452, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VI; 84521Z (2012) https://doi.org/10.1117/12.925250
Event: SPIE Astronomical Telescopes + Instrumentation, 2012, Amsterdam, Netherlands

Abstract

We have developed Water Vapour Radiometers (WVRs) for the Australia Telescope Compact Array that are capable of determining excess path fluctuations by virtue of measuring small temperature fluctuations in the atmosphere using the 22.3 GHz water vapour line for each of the six antennae. By measuring the line of sight variations of the water vapour, the induced path excess and thus the phase delay can be estimated and corrections can then be applied during data reduction. This reduces decorrelation of the source signal. In this presentation, we discuss the design of the WVRs, an uncooled quadruple filter radiometer capable of detecting water line temperature fluctuations to a sensitivity of 12 mK. The design process of the WVRs is discussed with an emphasis on the modelled sensitivity requirements, filter placement, radio frequency interference mitigation and we conclude by demonstrating how this water vapour radiometry system recovers the telescope's efficiency and image quality as well as how this improves the telescope's ability to use longer baselines at higher frequencies, thereby resulting in higher spatial resolution. We discuss a quadruple filter, uncooled 22.2 GHz Water Vapour Radiometer (WVR) system developed for the six antennae of the Australia Telescope Compact Array. The design process of the WVRs is discussed with an emphasis on the modelled sensitivity requirements, filter placement, radio frequency interference mitigation and we conclude by demonstrating how this system recovers the telescope's efficiency and image quality as well as how this improves the telescope's ability to use longer baselines at higher frequencies, thereby resulting in higher spatial resolution.

Citation Download Citation

Balthasar T. Indermuehle, Michael G. Burton, and Jonathan Crofts "Water vapour radiometers for the Australia telescope compact array", Proc. SPIE 8452, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VI, 84521Z (24 September 2012); https://doi.org/10.1117/12.925250

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