Australia's most high-tech CELLAR

The only deep-underground physics laboratory in the Southern Hemisphere is getting a very cool new toy—a fridge that cools things to temperatures 300 times colder than outer space.

The new facility, the Cryogenic Experimental Laboratory for Low-background Australian Research (CELLAR), will be a huge boost for Australian research, attracting international and multidisciplinary collaborations, and advancing the growth of Australia’s high-tech industry.

Dr Glen Harris—from The University of Queensland (UQ) and the ARC Centre of Excellence for Engineered Quantum Systems (EQUS)—said the centrepiece of the new facility is a high-tech cooling system called a dilution refrigerator that will be installed deep underground at the Stawell Underground Physics Laboratory (SUPL) in regional Victoria.

“Deep underground laboratories like SUPL are rare, with only a handful worldwide, and the number with high-tech cryogenic systems like CELLAR is even lower,” he said.

“We’re very excited to be able to create this unique environment for world-class research here in Australia, enabling ultraprecise experiments for fundamental science, and new cutting-edge technologies.”

Dr Ben McAllister—a CELLAR researcher from Swinburne University of Technology, EQUS and the ARC Centre of Excellence for Dark Matter Particle Physics (CDM)—said the key to CELLAR is the extreme shielding it provides from background noise.

“Our regular world is very noisy: everything at any temperature is constantly emitting light, as you may know if you’ve ever seen images from infrared or thermal cameras, and we’re being constantly bombarded with particles from space, called cosmic rays,” he said.

“But in physics and technology we’re often trying to detect individual particles, such as photons (particles of light) or electrons, which is very difficult if not impossible unless you can shield against these noisy background sources.

“With CELLAR, we reduce thermal noise in our experiments by cooling them in the dilution fridge to temperatures as low as 10 millikelvin, around 300 times colder than outer space.

“And being situated a kilometre underground in the Stawell Gold Mine means CELLAR is extremely well shielded from cosmic noise, because the particles from space that bombard us on the surface all day are absorbed by a kilometre of rock.”

CELLAR will become a reality thanks to funding awarded to a collaboration of researchers from around Australia as part the Australia Research Council (ARC) Linkage, Infrastructure, Equipment and Facilities (LIEF) funding scheme.

The $860,000 LIEF grant, combined with $305,000 in contributions from UQ, Swinburne, The University of Western Australia (UWA) and The University of Melbourne, will facilitate the purchase of two dilution fridges, one to be installed at SUPL and the other at ground level at Swinburne, hopefully by mid- to late 2024.

The second fridge will enable comparative research between the surface and deep underground, and allow researchers to prototype experiments before deploying them in SUPL.

Professor Elisabetta Barberio—another CELLAR researcher, from The University of Melbourne and the Director of CDM—said that as an open-access facility with unique capabilities, the team expects CELLAR to attract strong international collaborations with multidisciplinary teams.

“CELLAR will develop new technologies that will lead to a deeper understanding of the Universe and its fundamental constituents, produce key advances in emerging quantum devices, and open the door to the discovery of new physics processes,” she said.

“CELLAR will be key to educating the next generation of scientists and advancing the growth of Australian high-technology industries.”

As well as Dr Harris, Dr McAllister and Professor Barberio, the researchers involved in CELLAR are: Dr Chris Baker and Associate Professor Arkady Fedorov (EQUS, UQ); Dr Maxim Goryachev and Professor Mike Tobar (EQUS, CDM, UWA); Associate Professor Matthew Dolan and Dr Peter Cox (CDM, The University of Melbourne); Professor Darren Croton (CDM, Swinburne); and Dr Michelle Dunn (Swinburne).