A cool start to the year for CELLAR
A fridge that reaches temperatures 300 times cooler than outer space is due to be installed in the CELLAR facility in the Stawell Underground Physics Laboratory (SUPL) by mid-2025.
The dilution refrigerator will be based in SUPL while another fridge has already been placed above ground.
It will be among the first experiments to be undertaken in SUPL, the first deep underground laboratory in the Southern Hemisphere.
The Cryogenic Experimental Laboratory for Low-background Australian Research (CELLAR) aims to attract international and multidisciplinary collaborations, and advance the growth of Australia’s high-tech industry.
In late 2024, scientists undertook CELLAR-adjacent experimental work when Dr William Campbell and Dr McAllister brought Quartz Oscillators (provided by Quantic Wenzel) into SUPL to measure their frequency stability and determine the impact of cosmic rays.
Once the underground dilution fridge is operational, the scientists aim to extend this research into a cryogenic environment, potentially revealing new insights into oscillator stability in cosmic ray shielded conditions.
Dr McAllister, a CELLAR researcher from Swinburne University of Technology, the Dark Matter Centre and the ARC Centre of Excellence for Engineered Quantum Systems 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 has been made possible through 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, has facilitated the purchase of the dilution fridges aboveground and in SUPL.