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Summer 2019

Online Extra

Paulo Falco Cobra, instrumentation specialist at the National Magnetic Resonance Facility at Madison, stands with the large bags that hold recovered helium so that it can be stored until it's liquefied and reused as coolant for the facility’s spectrometers. Photo by Robin Davies.

For scientists looking to explore living things on an atomic level, there’s a decades-old but nevertheless astounding tool at their disposal. With biomolecular nuclear magnetic resonance (NMR) spectroscopy, they can probe the miniscule structures of biological macromolecules and identify how these structures relate to function. Such capabilities can be an enormous boon, for example, in the search for new and more effective pharmaceuticals.

NMR excels at uncovering molecular interactions between drugs and drug targets or between macromolecules themselves. NMR can also be used to probe the composition of small molecules in biological fluids, such as plasma, cerebral spinal fluid, urine, and cell or organ extracts. This type of structural work is important in many areas of research, such as the search for new antibiotics.

This is why researchers at CALS, and UW–Madison more broadly, are fortunate to have access to the National Magnetic Resonance Facility at Madison (NMRFAM). Housed in the Department of Biochemistry, it is home to state-of-the-art NMR technology and related techniques. The facility offers its users indispensable instrumentation, software, and expertise.

But the facility’s equipment requires helium to keep it cool. With worldwide supplies of the noble gas dwindling, NMRFAM has recently installed a helium recovery system to increase sustainability and cut costs.

All nine of the NMR magnets at NMRFAM are superconducting, which means that, as long as they remain cooled at liquid helium temperature (4 degrees Kelvin or about ‒450 degrees Fahrenheit), they behave like permanent magnets. The liquid helium used to cool each system boils off slowly and has to be replenished. The problem is that helium is a scarce, nonrenewable resource extracted from the ground, and it escapes from the Earth’s atmosphere when released.

“It’s rare to find new sources for helium, and the sites where it has been found are all running dry, so helium is getting more and more expensive to buy, and there are a lot of geopolitics involved,” says Paulo Falco Cobra, an NMRFAM instrumentation specialist. “When our helium costs reached $100,000 per year, we decided to invest in a way to efficiently recycle the helium on site and become more sustainable.”

NMRFAM applied for a supplement to the National Institutes of Health grant that supports the facility and was successful in obtaining funds to purchase a helium recovery system.

The recent installation was completed by Falco Cobra and NMRFAM’s now-retired instrumentation specialist Mark Anderson. The system recovers lost helium while filling the spectrometers. It can also recover the daily boil off from each magnet. The system collects the helium in gas form in large bags and then compresses the gas, runs it through a purifier to remove contaminants, and liquefies the helium to be put back into the spectrometers.

Once fully functional, the system will recover and recycle 80% of the helium used at NMRFAM, cutting costs down to just $20,000 per year and serving as a hedge against anticipated future price increases.

“Helium is a noble gas, so it is very stable and won’t degrade,” Falco Cobra adds. “It’s very exciting to be able to save money and help the environment by being more sustainable.”

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