Telescope Technology Turns Up the Volume on Innovation

Radio astronomy may not be widely regarded as fertile ground for nurturing commercial technology, but the efforts of researchers at the NRC Herzberg Institute of Astrophysics (NRC-HIA) have been doing just that. While refining electronic components as part of the most ambitious project ever undertaken in this field, the resulting hardware has attracted interest from well beyond the usual bounds of this discipline.

Artist's conception of the antennas for the Atacama Large Millimetre Array. Image courtesy of NRAO/AUI and ESO.

The focus of this attention is a new generation of Band 3 receivers, a set of extremely sensitive instruments designed for signals in the 84-116 GHz range. They will play a critical part in the operation of the Atacama Large Millimetre Array (ALMA), a powerful facility that is being constructed in the unrivaled astronomical setting of northern Chile's high altitude desert.

Once it is completed in 2011, ALMA will incorporate dozens of radio antennas that function as a single observing platform. This telescope is being designed to take in light with wavelengths on the boundary of the microwave and infrared parts of the electromagnetic spectrum. The cold gases of deep space emit this kind of radiation, which astronomers expect will offer unprecedented insights about the complex molecules found in these otherwise empty recesses of the universe, along with clues to how planets, stars and whole galaxies are formed.

Photo of the new generation of Band 3 receivers, a set of extremely sensitive instruments designed for signals in the 84-116 GHz range.

NRC-HIA has been developing receivers capable of picking up these faint signals around the three-millimetre wavelength section of the spectrum, dubbed Band 3. As part of ALMA, they will be vital not just for making astronomical observations, but also for aligning instrument panels and calibrating the system in preparation for these scientific activities.

The demands imposed by such technology are considerable. These receivers would be overwhelmed by the "noise" typically generated by electronic components, so they instead operate with superconducting circuitry in cooling chambers at temperatures of around -269^○ C.

Project manager Keith Yeung, an electronics engineer with the NRC-HIA Astronomy Technology Research Group (Victoria) has been heading up a team of 15 people that has been working on the amplifiers that will be used in these receivers. He and project engineer Stéphane Claude have worked on similar equipment for the James Clerk Maxwell Telescope (JCMT), a massive radio telescope based in Hawaii.

Claude recalls assembling an earlier generation of these receivers for the JCMT as part of his doctoral work, but he notes that the scale of this work was far different from ALMA. "Every time it was a one-off, a prototype," Claude recalls. "You put together the devices and a year or two later you're actually observing with it, and that's really thrilling."

In contrast, ALMA represents a much more ambitious undertaking, with many more partners and a much longer timeline. Yeung points out that while the JCMT required just one receiver for each frequency band, ALMA is expected to use more than 60.

"We don't have the luxury of fine-tuning and tweaking every bit by hand," says Yeung. "It would take us 100 years to do all these receivers."

The Atacama Large Millimetre Array (ALMA) VertexRSI test antenna constructed at the site of the Very Large Array near Socorro, NM. Image courtesy of NRAO/AUI.

He and Claude are still looking for a manufacturer who would be willing and able to produce a significant number of units meeting these exacting requirements. They know the challenge ahead, having faced the same issue when they sought a company to help them assemble the hundreds of amplifiers that are the heart of these receivers.

"There's one or two very specialized commercial companies that will sell cryogenic amplifiers like this, but none of them offer the wide bandwidth like the ones we're using," says Yeung, who notes that these firms see little commercial potential in these products.

In order to build the amplifiers, the NRC-HIA team eventually struck up a partnership with Nanowave Technologies Inc. of Etobicoke, Ontario, a firm that has established an expertise in sophisticated communications and radar systems. After a great deal of negotiating over production methodology, the project has set new standards for the company's approach.

"They are very energetic and keen to work with us in this area," says Yeung. "They are looking at it as an opportunity to expand their product line into other areas."

Artist's conception of the ALMA antennas in a compact array. Image courtesy of NRAO/AUI and ESO.

In fact, he and Claude have been invited to work with Nanowave on the firm's latest research endeavour, designing components associated with weather radar for aircraft. And while there may be few commercial prospects of specialized systems like the receivers, components like the cryogenic amplifiers have been attracting attention from further afield. Physicists from CEA, the French government's major technological research organization, have purchased two of these units, which will dramatically enhance the efficiency of data collection by these researchers.

"Using our units," says Yeung, "they expect to reduce the amount of their experimental time by a factor of two, because the noise of our amplifier is so low."

In this way, researchers on the cutting edge of astronomy have not only been able to take advantage of developments in the world of commercial electronics; they have also contributed to this dynamic marketplace.

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