12-mm Receivers for the Australia Telescope Compact Array

Brief snapshot summaries of The Technology ,The Science and The Benefits for Australia
of the 12-mm receiver upgrade project are presented here. Further details for scientists and engineers are given in the Technical And Scientific pages.

The technology:

Seven new receivers will be built for installation on the newly surfaced anntennae of the Australia Telescope Compact Array. This number includes one spare. The new 12-mm receivers will be cryogenically cooled and will cover the frequency range 16-25 GHz. Initial design studies are complete and construction of the first receiver at ATNF commenced in 1998. It is anticipated that the receivers will be ready towards the end of 1999. The amplifier electronics are being built at ATNF using surface-mounted devices, enabling the whole package to be much smaller than would otherwise be possible. An innovative orthomode junction for the receivers, which converts the waves received by the feed horns into two linearly polarised signals, is being designed and constructed at ATNF.

The technical and scientific pages contain more details on the design and construction of the receivers.

The science:

Currently, the smallest wavelength radiation that can be measured with the Australia Telescope Compact Array is 30mm. A receiver system based around 12mm will provide increased angular resolution, enabling more detailed images of astronomical objects to be made, and will give access to a very important spectral region. For example, with the new system it will be possible to observe the continuum emission from SN 1987a, both its polarization and evolution. SN 1987a is a supernova, the remnants of the explosive death of a star . It was first observed in 1987 in our nearest neighbour galaxy, the Large Magellanic Cloud. Similar studies will also be possible on other supernovae, as well as active galactic nuclei and other astronomical sources.

Astronomers may also be able to study molecules such as carbon sulfide and HCO+ around SN1987a. Studying the molecular emission from the supernova gives more information on the microscopic mixing of the supernova material and the physical conditions in the supernova region.

Observations of water masers and methanol masers will also be possible with the new system. Such observations are used to study molecular flows around star-formation regions to give more information about the physical conditions and chemical composition of material in the process of forming new stars.

Emission in the 12mm wavelength region is also ideal for observations of arcminute scale anisotropies in the cosmic microwave background, important for our understanding of the very early history of the universe.


The technical and scientific pages contain more details on the science that can be done with the new 12-mm receivers.

The benefits for Australia:

During the construction of the Australia Telescope National Facility the Receiver Group at the ATNF in CSIRO further enhanced its reputation as a world leader in specialist receiver construction. The outstanding reputation of the group is demonstrated by the fact that they have since built and sold astronomical receivers for Japanese and Chinese astronomical organisations, as well as building receivers for Galileo and SETI. They are continuing to develop innovative instrumentation associated with the construction of the 12-mm receivers and so are maintaining their, and thus Australia's, reputation as world-leaders in innovative engineering.

The development of the new receivers will enable CSIRO engineering and scientific staff to continue to transfer state-of-the-art technology in the microwave, RF and IF fields to Australian industry. As construction of the Australia Telescope has already demonstrated, the experitse continuing to be developed at ATNF will place our industrial partners at a distinct competitive advantage.
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