The coldest place in Victoria

August 11 / 67

Dr Laurens Willems van Beveren with the Dilution Refridgerator
Dr Laurens Willems van Beveren with the Dilution Refridgerator

The School of Physics’ new cryogen-free dilution refrigerator can create the coldest place in Victoria, cooling down to about 20 milli-Kelvin, almost the point of absolute zero, the null point of any temperature scale.

Zero Kelvin is defined as -273.15 °C.

The only refrigerator of its kind in Australia, the AU$600 000 machine was shipped from Leiden, The Netherlands, and was operating within a week of delivery.

It will advance research in some of the key fields the University’s physicists focus on, including quantum systems and solid-state physics. Solid-state physics is the study of how the large-scale properties of solid materials result from their small-scale properties, while quantum systems research examines how nanoscale structures behave differently to large-scale objects.

Senior Postdoctoral Research Fellow and lead of the University’s Quantum Measurement Program Dr Laurens Willems van Beveren said the machine was necessary to further the school’s research endeavours.

“What we’re striving for is better understanding of fundamental physics,” he said. 

“At extremely low temperatures, some of the fundamental properties of certain materials appear, and we needed the refrigerator to create those temperatures. We’re striving for breakthrough science, and the fundamental improvement of our knowledge of the solid state.”

Dr Willems van Beveren explained the way in which extreme cooling allowed for specific experiments: “Imagine you’re an electron and you’re leaving Flinders St Station, and you’re trying to make it to University of Melbourne for a physics class, so you rush up Swanston St, but it’s busy, traffic is bad and there are many people in the way.

“What happens is you try to divert around people and objects, and it slows you down – this is like the vibrations in the crystal of each molecule. If everything stood still, you could get to the University much faster – it would be a low resistance path. This is what cooling to a very low temperature does, it clears out these impediments and creates a clear path for the electrons to travel on. 

“This lets researchers undertake very specific, detailed experiments. When you freeze samples like this, all the nice physical properties of the solid-state rise to the surface.”

 

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