When was the last time you knowingly encountered helium, the gas that makes balloons float and children—OK, adults too—giggle and talk in high, squeaky voices after inhaling it? Likely at a birthday party, wedding, or another celebration, right?
Helium, however, has many applications beyond party balloons. Pure, high-quality helium is critical to several industries and technologies, including quantum computing.
“Many quantum computing technologies use helium,” said Steve Sanders, director of engineering at Quantinuum, which develops trapped-ion quantum computing technologies. “We use it to keep our ion traps very cold because they operate better below 50 degrees Kelvin. The helium also has the effect of lowering the gas pressure inside our physics packages and keeping the few remaining gas atoms cold. Fewer gas atoms mean fewer collisions with our ions. And cold gas atoms have far less energy, so even if they collide with our ions, they don’t disturb them.”
Found among the stars, helium is one of the most abundant elements in the universe, second only to hydrogen. On earth, where it’s formed from alpha-particles of radioactive elements decaying beneath the surface, helium is a finite resource. And that’s why Quantinuum has significantly invested in staff and infrastructure to reuse as much helium as possible.
“We recognize the physical and socioeconomic impacts of both limited natural resources and climate change, so it’s crucial for us to operate as sustainably as possible,” said Tony Uttley, president and chief operating officer at Quantinuum.
Andy Miller, an engineer at Quantinuum, spends his days managing and maintaining the extensive helium recovery system at the company’s Colorado campus. (Quantinuum has a smaller system at its laboratory space in Minnesota.)
“Our helium liquefaction system is a process plant that converts helium from a gas into a liquid. That liquid is then moved into the labs where it provides cooling to the quantum computing application. As it provides cooling, it becomes a gas again and then is transported into our recovery pipeline, which is installed throughout the facility, and the recovery piping leads to a big gasbag,” Miller explains.
“This gasbag is a giant balloon that fills up with gaseous helium. And as that balloon fills up with helium, it is monitored by a level sensor that measures the size of the gas bag. Once the bag inflates to a certain volume, it turns on a high-pressure compressor. The high-pressure compressor then pulls helium from the gas bag and sends the helium over to high-pressure storage. The helium is stored in high-pressure cylinders which are 20 feet in length and two feet in diameter. It's stored as a high-pressure gas until it's ready to be liquefied again and sent back to the labs to continue the cooling and recycle process.”
This process enables the team to recover and reuse large amounts of helium.
“Helium is an absolutely 100% nonrenewable resource,” Miller emphasizes. “Once we pull helium out of the ground, it is so light that it will float up out of the atmosphere. It’s important we recover and reuse as much of it as possible.”