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.
Go to MNRF
Projects Page
Go to MNRF Home Page
Go to ATNF Home Page
Last update by Michelle Storey. 18/3/99