Workshop on the broadband backend project for the Compact Array

A workshop was held at the ATNF headquarters in Marsfield on 13 September 2004, to discuss the technical specification of the planned broadband backend for the Compact Array, as well as its scientific capabilities. The Compact Array Broadband Backend (CABB) will be the correlator that replaces the current correlator and is aimed at providing: an increase in the Compact Array continuum sensitivity of up to a factor of four (due to a maximum bandwidth of 2 GHz at each of 2 IFs in 2 polarisations), greatly enhanced spectral-line performance, connections to additional antennas (such as the New Technology Demonstrator), and new correlator technologies for Square Kilometre Array (SKA) demonstrations. The CABB project is funded by the Major National Research Facilities Program (see ATNF Newsletter #45).

The workshop was organised by the Australia Telescope Users Committee (ATUC) and the CABB project scientist, Jim Caswell, and was an opportunity for the CABB project to present the base technical specifications of the new correlator to the user community. The CABB project manager, Warwick Wilson did exactly this during an interesting talk. The CABB will be an `FX' style correlator, in contrast to the current `XF' Compact Array correlator, and will use digital filter banks to allow very flexible choices of observing bandwidths and numbers of frequency channels.

A series of talks were then aimed at describing some of the scientific applications of the new correlator. Of note is the proposal that the CABB be eventually used as a real-time correlator for Australian VLBI, once high speed optical fibre connections are installed between all Australian telescopes. Also of note was the interest in using the CABB for frequencies from 1 – 10 GHz. Initially the CABB will be of most utility at 1 cm and 3 mm, where contiguous frequency bands of greater than 2 GHz are available. The Compact Array and CABB will allow important short term scientific gains to be made at these frequencies. The use of the CABB in the 1 – 10 GHz range will need to wait until the Compact Array front-end electronics can be modified to give broad bands.

The presentations given at the workshop are available on the ATNF meetings archive. The discussion from the meeting will be used to refine the technical specifications for the CABB, which will be presented to ATUC meetings over the next 12 months. For further information on the CABB, please contact Jim Caswell, CABB project scientist.

Steven Tingay
ATUC Chair
(stingay@astro.swin.edu.au)