3-mm Receivers for the Australia Telescope Compact Array

Brief snapshot summaries of The Technology ,The Science and The Benefits for Australia
of the 3-mm receiver upgrade project are presented here. Further details for scientists and engineers are given in the Technical And Scientific pages.

The technology:

Six new receivers will be built for installation on the newly surfaced anntennas of the Australia Telescope Compact Array. The new 3-mm receivers will be the first astronomy receivers to use cooled Monolithic Microwave Integrated Circuit (MMIC) technology for low-noise amplifiers and conversion components. Research into the design, fabrication and application of indium phosphide (InP) MMIC's has been funded with $2.2M awarded to the ATNF, in partnership with CSIRO Telecommunications and Industrial Physics (CTIP), from the CSIRO Executive's Special Fund. As well as providing advanced electronic devices for the MNRF work, the MMIC program will augment greatly the range of high-frequency test equipment available to ATNF engineers involved in the MNRF upgrades.

Prototype 3-mm receivers, cryogenically cooled to 20 degrees Kelvin and covering a frequency range of roughly 85-115 GHz are already being designed and built. The project involves;
  • the design and construction of suitable feed horns - these will either be corrugated on the inside or dielectrically loaded
  • the design and testing of suitable Orthogonal Mode Transition components and mixer systems
  • the development of suitable low-noise amplifiers. Ultimately it is hoped that MMICs using Indium Phosphide transistors will be used .
  • the design and construction of receiver housing and mounting frames etc.
The technical and scientific pages contain more details on the design and construction of the receivers.

The science:

By looking into space with receivers that can detect radio emission at wavelengths as small as 3-mm it is possible to investigate chemical processes occurring in space that cannot be detected at longer wavelengths.

Many interesting interstellar molecules will be observable with this system. One example is the carbon sulfide (CS) molecule, which is commonly found in the gas between stars in our own and other galaxies. Radiation from the CS molecule is used to investigate the flow of matter onto protostars - dense clouds that are collapsing to form new stars. Such radiation will be able to be detected with the new system, which will enable astronomers to probe regions of star formation that are otherwise inaccessible.

Radiation from molecules at mm-wavelengths can also indicate the presence of cool molecular gas in other galaxies, which can be used to study the processes that power active galaxies, and to probe the clouds of cool gas at cosmological distances which are the progenitors of the galaxies we see today.

The technical and scientific pages contain more details on the science that can be done with the new 3-mm receivers.

The benefits for Australia:

The design and production of the state-of-the-art amplifiers using MMIC technology involves leading-edge electromagnetic and fabrication research. Such research is strategic for other future applications of MMIC technology, such as broadband mobile telecommunications. Australian expertise at the CSIRO Division of Telecommunications and Industrial Physics is being exploited here. The ATNF expects to utilise Australian industry to produce these systems, and to provide prototypes and engineers able to transfer to industry expertise in short-wavelength technology, a rapidly expanding field in telecommunications. The Benefits to Australia page contains more details on the benefits to Australia of the MNRF AT Upgrade Project.
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Last update by Michelle Storey. 18/3/99

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