A global helium shortage has created a crisis for scientists across Canada. Chemists and other researchers depend on this unique element to cool superconducting magnets to 4.2K for nuclear magnetic resonance (NMR) experiments and certain low-temperature studies. However, helium supplies are limited, demand from new markets is increasing, and the United States has been emptying its massive Bureau of Land Management (BLM) Federal Helium Reserve, with the last public auction having taken place in 2018. This combination of pressures has caused price increases and shortages around the world, including Canada.
Researchers use superconducting magnets that fall into two types: those that would be extremely expensive and potentially difficult to replace if they were ever warmed up; and those that can cope with warmups. The former group includes magnets for NMR, Magnetic Resonance Imaging (MRI), Magnetoencephalography (MEG), and similar techniques; the latter includes low-temperature physics instruments.
NMR spectrometers and magnets for MRI or MEG cannot easily be turned off or left without regular helium refills. Any warming-cooling cycle incurs the expense of additional liquid helium, along with days or weeks of downtime; nor are these instruments even guaranteed to recover their original level of performance afterward.
As a result of shortages, “we have had to adapt how/when we order helium,” says Pedro Aguiar, NMR Facility Manager at the Université de Montréal, whose facility is slated to move to a new building later this year. “Owing to the difficulties in obtaining liquid helium we took the decision in January 2019 to move up the decommissioning of an older magnet, which would not move to the new science complex. The loss of the instrument has resulted in maximum loading of remaining instruments, causing frustration for our users, however, the elevated risk of a spontaneous quench of the magnet due to insufficient cryogens was too great.”
The supplier providing Aguiar with helium has increased prices by 300% in the past year. When low-temperature physicists face that kind of rising cost or outright shortage, they may be forced to take a break from their work — leaving important research undone, student projects delayed, and grant applications weakened. In some cases, they might abandon the work altogether, as did Peter Grutter, who chairs McGill University’s Department of Physics. He conducts world-leading projects with atomic force microscopes, which he uses to study properties of materials such as graphene at very low temperature in very high magnetic fields. But, after a four-fold increase in the cost of helium over the past year, he says that “we have had to drop two lines of research. Helium is simply too expensive.”
A helium recovery system can offer a significant alternative to the traditional cycle of purchasing and using helium. Typically, helium used for cooling superconducting magnets has been allowed to boil off passively from the magnet as it warms. However, within the past few years, commercial systems to collect, compress, purify, and liquefy the helium on site have been developed and even installed in NMR and physics labs across the country.
Tony Montina, Director of the Magnetic Resonance Facility at the University of Lethbridge has been running a helium recovery system for 10 years. The system was funded by a private donation enabling helium recycling for an older 3T helium MRI scanner that used 12 litres of helium daily as well as a 4.7T animal MRI system that used 4 litres of helium daily. The human scanner has since been decommissioned, and three NMR spectrometers have been connected instead.
“We go through about 2,400 litres [of helium] per year,” says Montina, “and our recovery rate…is 90+%.” He adds that recovery also saves about $60,000 annually on helium costs, and a recent 25% price increase imposed by his local supplier does not cause him sleepless nights.
One of these systems can cost several hundred thousand dollars, which represents a major upfront investment. Nevertheless, the business case improves with each helium price increase. Just as importantly, recovery eliminates delivery shortage problems — there is almost always helium available once the system is in place.
Other systems that avoid purchasing helium continuously include “dry” magnets, where dilution fridges or pulse-tube cryocoolers replace the traditional helium-cooled magnet, and refrigeration systems mounted to individual magnets that continuously cool and circulate helium. In many applications, this technology is preferred for new instruments.
In the United States, pressure to mitigate the effects of helium shortages has been steadily mounting since the BLM decided to privatize its stockpile in 1996. These efforts increased through the 2010s, driven by the effects of plant maintenance and geopolitical events in the Middle East, a major source of helium. In 2016, the American Physical Society, the American Chemical Society, and the Materials Research Society issued an action plan to cope with helium needs. In 2019, the National Academies decadal survey for materials research encouraged funding for helium recovery systems.
Recently, the National Institute for General Medical Sciences (NIH) has issued a grant program designed specifically to fund helium recovery systems for NMR facilities. The National Science Foundation (NSF) has also been funding these facilities at an accelerated rate. Within Canada, no such dedicated, organized initiative focused on helium is known to exist, so funding has been obtained through a patchwork of other avenues, including Canadian Foundation for Innovation (CFI) and NSERC’s Research Tools and Instruments Grants Program. A current informal survey of NMR facilities across the country shows that recovery systems have been installed at just a few sites, although seven or eight others using large volumes of helium are seriously considering this prospect.
For anyone who may be weighing this considerable investment, there are three major arguments. The first is economic: as helium costs increase, the system pays for itself more quickly. After taking maintenance and electricity costs into account, a user of 3000 litres per year will probably find that the break-even point is reached in five to eight years.
The second argument is environmental. Allowing helium to boil off into the atmosphere and from there into space is wasteful. Extracting it from natural gas deposits requires a good deal of energy and transporting it from the US or overseas to Canada generates significant amounts of greenhouse gases. Compressing boil-off helium and liquefying it in the lab is also energy-intensive, but less so than extracting it, compressing it, and liquefying it at source.
The third argument is that shortages are largely mitigated if an efficient recovery system is in place. Topping up the system with 10% of annual helium usage is less worrying than receiving helium several times throughout the year. In fact, deliveries can be in the form of helium gas, which can be liquefied by the system, rather than liquid helium. For smaller sites located at a distance from the main distribution centres, this argument is the most important. As long as helium-cooled superconducting magnets remain a significant focus of chemistry, physics, and medical research, the cost of helium will be a worry to researchers. How can Canadian researchers convince their funding agencies that their scientific programs depend on access to this element? The answer, like a helium balloon, remains up in the air.