Oxford Cryosystems Ltd - Helping SKAO’s mid-frequency telescope keep its cool
Image credit: EMSS Antennas/Alexander Krebs
In the heart of South Africa’s Karoo desert, the SKA Observatory is tuning into the universe, building one of the world’s largest radio telescope arrays. The UK is a key partner, hosting the global HQ at Jodrell Bank, near Manchester. Science goals include exploring the origins of our universe, using pulsars to track gravitational waves, and studying galaxy formation.
Cryogenic Innovation in the Karoo
The SKA-Mid telescope will consist of 197 dishes, operating in the radio frequency range from 350 MHz to 15.4 GHz, enabling astronomers to probe the universe to study distant stars and galaxies. However, the Karoo – the telescope’s remote home – is an unforgiving place. Temperatures drop to -15°C in winter and reach over 40°C in summer. To detect the faint radio signals emitted by far-off celestial objects some of the telescope receivers must remain exceptionally cold – approximately 20 K (- 253°C). Achieving and sustaining cryogenic temperatures in such extreme conditions demands the development of innovative cooling technologies tailored to withstand these environments.
To meet these challenges, the SKAO required a bespoke low power cryogenic system to cool several single pixel feed receivers, Bands 2, 5a and Band 5b, for the SKA-Mid telescope. The system needed to include helium compressors capable of providing and sustaining cryogenic temperatures alongside cryocoolers directly connected to each receiver. This cryogenic system helps to reduce thermal noise and increase the sensitivity of the telescope.
Why Oxford Cryosystems?
Oxford Cryosystems, based in Long Hanborough, Oxfordshire, were ideally positioned to deliver this solution. Founded by a crystallography professor from the University of Oxford, the company has grown into a world-leading supplier of cryogenic and low-temperature systems over the past forty years. Their technologies support advanced science research for international research facilities such as ANSTO (Australian Nuclear Science and Technology Organisation) and Oak Ridge National Laboratory, and national facilities such as ISIS Neutron and Muon Source, and Diamond Light Source, with applications spanning pharmaceuticals, nano-technology, biomaterials, semiconductors and other advanced materials.
Their long-standing collaboration with University of Oxford Astrophysics Department spans over 15 years, supplying cryocoolers and a water-cooled helium compressor for the C-BASS telescope in South Africa. In 2014, following University of Oxford’s introduction to South Africa’s EMSS Antennas, Oxford Cryosystems ruggedised their cryocoolers and supplied 192 of them for MeerKAT – the precursor to the SKA-Mid telescope – in the Karoo, South Africa, built and operated by SARAO.
By 2015 the company had also secured a contract from University of Oxford to design and develop a ruggedised version of their helium compressor, tailored specifically for the SKA project. The work was funded 50:50 by STFC and the company. This journey culminated in 2023, when Oxford Cryosystems were awarded the SKAO contract to supply cryocoolers and compressors for the SKA-Mid telescope.
Alex Renshaw former Director and co-owner of Oxford Cryosystems said, “As an SME, our flexibility and willingness to develop, adapt and customise our products through talking to academics and customers to understand their requirements was key to the success of the project.”
Mike Jones, Professor of Experimental Cosmology at the University of Oxford, said, “We first met Oxford Cryosystems when we were looking for low-cost, low-power GM coolers for radio astronomy. We were excited to discover a local company who had exactly the products we needed and who were happy to support these products in what, for them, was a new application. When we later became involved in the SKAO it was natural to turn to Oxford Cryosystems to design a new compressor to the SKAO’s requirements. The combination of our specialist end-user knowledge and their technology enabled us to work together easily and come up with a bespoke solution.”
A True Partnership
Reflecting on the partnership, Managing Director Dan Bodio remarked, “Working with SKAO over the past ten years has been a game changer for us. From those early technical discussions to delivering on MeerKAT, MeerKAT+, and now SKA-Mid, it’s been a true partnership. This project has pushed us to engineer tougher, smarter systems, capable of withstanding some the harshest environments on Earth. We’re really proud of what we’ve delivered here and even more excited about where it’s taking us.”
“Oxford Cryosystems will provide 80 coolers for each of the Band 2 and Band 5 receivers as well as the helium compressor in the first deployment of dishes,” says Mark Harman, SKAO Dish Project Manager.
“The cryocoolers provide innovation and demonstrated efficiency with reliability to maximise the telescope’s observing time when cooling the detectors to -260°C. The products are well established and are an excellent example of industry-academia collaboration. The SKAO looks forward to continuing to work with them in the future.”
“This project was transformational for Oxford Cryosystems. We are proud to be part of such a massive project, and as a direct result we have developed a new, bespoke product, ruggedised low power air-cooled K450-AC3 compressor, designed and built for outdoor use, that can operate in extreme conditions such as the desert environment. This has opened a new market to us in radio astronomy, putting us top of the list for future work. It has allowed us to compete internationally and given us the confidence to look at new markets that we may not have otherwise considered.”
Dan Bodio, Managing Director
What was the Impact on Oxford Cryosystems?
The initial project, to design and develop the compressor with the University of Oxford, led to further contracts – 3.5kW air-cooled compressors for MeerKAT+, compressors and coldheads manufactured for the SKAO, and coldheads for the wideband receiver for the MeerKAT extension.
The work has also strengthened the partnership with the University of Oxford. Dan says, “We worked closely with University of Oxford to ensure that the cooling performance, power consumption, and the stringent requirements for reducing radio frequency interference were met. The University tested various prototypes in their lab, to check the performance of the compressors across the pressure and temperature ranges required, which, at the time, we couldn’t do in the factory.”
In 2022 the company had invested in a new factory in Oxfordshire, which enabled them to deliver the project.
“This work allowed us to really see the fruits of our investment in the new factory. We had to reconfigure the factory to deliver the SKAO work, and the outcome improved our infrastructure even further. It has increased our turnover, allowed us to take on new staff and given us a new strategic direction. The company has more than doubled since 2021, fuelled in part by the SKAO and related work. It has been great for our reputation to be involved in such a prestigious project, positioning Oxford Cryosystems as innovators in radio astronomy on the global stage."
Dan Bodio, Managing Director
