MNRF1996 Upgrade:
3-mm System for the ATCA
MNRF1996 Upgrade: 3-mm System for the ATCA
The System
The Science
Related Information
Project Personnel
Project Leader: Graham Moorey, ATNF Receiver Group.Latest News
-
The ATCA 3mm installation is now completed
and five antennas are operational in the range
from 85 to at least 100 GHz.
Useful Links
- "First Light" (30 Nov 2000)
- Press Release (8 Dec 2000)
- ATNF Newsletter (Feb 2001)
- ATNF Annual Report 2000
- Millimetre Science Workshop (8 Dec 2003)
The System
System Parameters
| RF bandwidth: | 85 - 115 GHz (*) |
| Maximum baseline: | 6 km (+ Mopra) |
| Number of receivers: | 6 + 1 spare (+ Mopra) |
| System temperature: | 180 K with InP MMIC amplifiers at 100 GHz |
| Polarisation: | dual |
| Comments: | to be packaged with the 12-mm receivers |
(* While the precise upper frequency limit of the upgrade is still somewhat uncertain - being dependent on the performance attainable with leading-edge technology - indications are that coverage up to 115 GHz may be possible. However, in line with the MNRF Technical Advisory Committee recommendations, the ATCA performance below 100 GHz will not be compromised unduly in order to gain this band extension.)
(see also the original Project Definitions)
Here is the overall design of the prototype ATNF high-frequency receiving package and here the result as of September 1999. First tests of 12mm system at the ATCA were carried out in October 1999. The 3mm GaAs MMIC amplifiers failed to cool and we proceed with InP MMIC amplifiers, currently in production, instead. Both the 12mm and 3mm receivers are contained in a common cryogenic dewar, with the separate feed horns being moved to the secondary focus of the Australia Telescope Compact Array antennas using the existing rotator positioning system. Provision has been made in the dewar for a future 7mm receiver. Note that the 3mm feed horn is cooled to 20 K to minimize losses and that the 12 mm receiver is used about 100mm off-axis during phase correction of 3mm observations. All receivers in the dewar are dual-polariztion types, with polarization splitting achieved using waveguide, rather than the originally proposed wire grid components.
Projected ATCA mm-performance
- ATCA upgrade related notes (by Ravi Subrahmanyan)
- Comparison with other mm-interferometers (by Bärbel Koribalski)
Science Results from July 2001
- Centaurus A (HCN (1-0), HCO+ (1-0), and HNC (1-0) absorption spectra)
- NGC 253 (HCO+ (1-0) emission spectrum)
- Circinus (HCO+ (1-0) emission spectrum)
- Eta Carina (short continuum observation)
- 1921-293 (searching for redshifted CO: z = 0.351 => 85.260 GHz)
- IRC+10216 (HCN(1-0), C_3N(9-8), HNC(1-0), and SiS(5-4) emission spectra)
- N113 (HCN (1-0) and HCO+ (1-0) emission spectra)
- N159 (HCN (1-0) and HCO+ (1-0) emission spectra)
- N6334 I(N) (SiO (2-1 v=0) mosaic)
- N6334 I(N) and AHSco (SiO (2-1 v=1) and SiO (2-1 v=0); 276m baseline)
Results from January 11, 2001
Results December 10, 2000
- SiO masers
- HCO+ absorption in Centaurus A
- Astrofest powerpoint presentation of the recent millimetre results
Related Information
Links to Millimetre Telescopes, Instruments, etc.Lovas Spectral Line Catalog (most amazing !!)
A four-page pamphlet describing the ATCA high-frequency (mm-wave) upgrade in simple terms (PDF File)