Untitled Document

Small dishes:
> Small dishes - Solid surface
> Small dishes - Mesh surface
> Small dishes + focal plane arrays

Aperture arrays:
> Aperture plane Array (AA)

> Small dishes + focal plane arrays

Two projects have been funded to take this part of the Reference Design forward and demonstrate its scientific capability. In Australia, the extended New technology demonstrator (xNTD), and in South Africa, the Karoo Array Telescope (KAT).

> The xNTD

The technology objectives of the xNTD are:
• 10x10 Focal Plane Array (FPA) operating over the frequency range 800-1700 MHz, on upto 20 parabolic reflector antennas (probably 15 m diameter)
• RFI and spectral line ripple cancellation using FPA (commercial applications are possible)
• RF and IF beam-forming to give extremely wide fields of view
• Polarization purity
• Correlation of large number (at least 20) of independent beams
• Wide band operation with low rfi levels
• Proof of infrastructure in remote desert environment (power supply, on-site data transport).
• Correlation of a large number of (typically 20) antenna stations, and 20 independent beams being formed
• Real-time VLBI using high speed fibre-optic data links with other antennas forming long baselines on the continent of Australia
• Multiplexed VLBI exploiting wide field-of-view and multiple beams
• Special purpose signal processors (eg for pulsar searches) using phased array beams
• Operational and processing software development.

Science Objectives:
HI emission survey to z ~ 0.1
• HI absorption to z = 1
• Transient source searches and continuum survey 1.2 – 1.4 GHz
• Galactic HI emission
• Pulsar survey (with new backend)
• Probe galactic and extragalactic magnetic fields
• Multiplexed VLBI on faint sources in deep imaging over wide field-of-view, with phase referenced calibration
• OH megamasers to z ~1.

> The Karoo Array Telescope (KAT)

As part of the SKA international collaborative project, South Africa has funded a science demonstrator radio telescope which will be a scaled-down version of the SKA (about 1% of the collecting area) to demonstrate its capabilities and capacity to build and support major science instruments. Research and development programmes to develop the technologies for the telescope are ongoing. Following completion of the prototyping phases, the telescope will be built in the Northern Cape between 2007 and 2010 at the Karoo site near Carnarvon.

The research and development, design and construction of the Karoo Array Telescope is a truly international effort, led by a South African team. An International Reference Group of leading astronomers and engineers provides input as and when required. Joint teams have been established with universities and industry in the UK, Australia, the Netherlands, Germany and the USA to develop the cutting-edge technologies which are necessary for the new telescope. Exchange programmes and support (bursaries and grants) for MSc and PhD students have been established to develop the high-level engineering and science skills required to build and operate the telescope. An MSc course on technology, primarily for women, is also planned.

KAT will be a working, integrated instrument with an aperture of at least 3,000 m2 (Ae/Tsys > 50), with:
• At least 10 steerable beams in 40 square degrees field of view
• At frequency range of 700MHz - 1.75 GHz with 0.5 GHz aggregate bandwidth,
• Dual polarization,
• It will be operated remotely, requiring only minimal on-site maintenance and resources.
• It will have a management system, operating system, maintenance system and a science programme under way. What does this mean?
• It must be capable of doing world-class science, and so will have the capability to do wide-field imaging, pulsar searching and timing, spectroscopy, continuum radiometry and VLBI data recording.
• The science system to support the instrument (to do the science) will be developed by the South African Astronomy Frontier Programme.
• The technology of choice is likely to be 20 parabolic reflectors, each of (15) fifteen meters diameter, each equipped with a 10x10 dual-polarization focal plane array. The telescope will be designed so as to have a modular and scalable upgrade path

More about this design:
White paper : 15 m dishes + FPA, 2004 - PDF
xNTD - ATNF - The New Technology Demonstrator
KAT - SKA South Africa - The Karoo Array Telescope

<- Back to previous page