Mopra 3mm MMIC receiver upgrade
First light for the new Mopra 3mm MMIC receiver. Courtesy Jürgen Ott and
During the period 12-30 September 2005, Mopra has been shutdown for
a substantial upgrade. Key components of this upgrade are
- Replace the 3mm wavelength SIS receiver system, with a 3/12mm MMIC system.
The new system includes noise diode calibration.
- Upgrades to cryogenics, primary monitoring, and system monitor and control
associated with the new receiver.
- Replacement of the VMS/Solaris-based observing software with a Linux-based system.
- Installation of a broadband intermediate frequency system from antenna to
- Installation of a segment of the MOPS digital filterbank back-end.
The new receiver has been installed. This is a tuner-less system (the old
tuning PC, power metre and spectrum analyser have been removed). Good performance
is possible from 77 to 117 GHz in two orthogonal polarizations.
System temperature measurements (at
the receiver horn) are good.
Optical alignment and focus have been completed, and a new
pointing solution installed. The beam patterns are good.
The observing control now runs on a Linux system. Some minor
issues are being worked through. The VMS system will be retired to observers.
Installation of hardware to drive the noise diode has been completed,
although the use of it has not been integrated with the observing system yet.
The broadband intermediate frequency system has been installed and is
The first segment of the MOPS filterbank saw "first light" on 14 October.
Spectrum of deuterated water in Orion near 80 GHz. Courtesy Jürgen Ott.
System temperature at the horn. Courtesy Graeme Carrad.
Checking the mechanical alignment of the receiver package.
Beamshape from an observation of an SiO maser. In the shaded areas, contours
are at increments of 10%. In the clear areas, the increment is 1%. Peak
sidelobe is about 8%. Tick marks are at 10 arcsec increments. Plot courtesy
of Tony Wong.
First spectrum from MOPS filterbank - W Hydra in SiO. Courtesy Warwick Wilson.
Original: Bob Sault (26-Sep-2005)
Modified: Bob Sault (14-Oct-2005)