New helium liquefier system saves researchers time and money

by Benjamin White

After five years of planning, designing and building, NQPI finally has a renewable source of helium, one of the most important and expensive materials used in research like scanning tunneling microscopy (STM).

Ohio University's new helium liquefier facility, housed in Clippinger Research Annex, cost roughly $800,000 and will pay for itself in four to seven years, according to NQPI director Dr. Arthur Smith.

“For us, it's an economical issue as well as having a much easier, plentiful, efficient and reliable source of helium for our experiments,” he said.

Researchers use helium in heavy amounts to help cool their STM systems to the point where molecular motion slows, allowing for clearer readings. Dr. Saw-Wai Hla, an NQPI member and just one of several helium users, consumes as much as 200 liters of the precious element per week, which would cost up to $150,000 per year (if he could afford continuous operation). After scientists used the helium, it would vaporize and vanish into the atmosphere (poof!), never to be used again.

The new helium liquefier, which Smith believes is the first in Ohio, will recapture the helium gas and convert it back into its liquid state, ready to be reused.

The quantifiable advantages to the new system are simple: the university will no longer have to pay for mass amounts of liquid helium, and the gas will not be released into the environment. Other benefits will appear with time. Prior to NQPI's acquisition of the liquefier, scientists had to budget their helium usage into their grants, and sometimes labs could not perform research, waiting until a shipment of helium arrived.

Howard Dewald, interim dean of OU's College of Arts and Sciences with a background in chemistry, seemed proud of the new piece of machinery, which he helped plan and finance.

“It seemed like the right move to make,” he said. “Grants were key in being able to do the work.”

Besides the Graduate Education and Research Board (GERB) grant, which helps fund NQPI, OU's Department of Physics and Astronomy and an 1804 grant helped shoulder the costs. NQPI's grant for global collaborations - the Partnership for International Research and Education (PIRE) - also contributed $150,000.

Doug Shafer, an OU mechanical engineering graduate and current mechanical systems technician within the Department of Physics and Astronomy, was key in helping plan and construct the unique and complex system in a challenging environment.

“We have a problem with vibration, and we've [had to make] some time-consuming expensive modifications,” said Shafer, who originally lobbied to build an addition to Clippinger Laboratories to house the machine. Humidity and air control also posed hurdles in the construction of the liquefier, which takes up two separate rooms. The recently-renamed Clippinger Research Annex, which lies only yards away from the research areas at Clippinger Laboratories, used to be a zoology research center, but it now works quite well as the home for the new machine.

The helium liquefier system, which took between six and eight months to install after the rooms were obtained and fixed and electrical power was put into place, begins with piping from each lab (currently three) which use the helium. The pipes bring used helium gas, which is pumped into a giant inflatable sack. From there, the gas passes through a compressor and into 18 storage cylinders (at least twice as many will be purchased in the future), where they wait to enter the helium liquefier itself, which uses low temperature and high pressure to create the Joule-Thompson effect, turning the gas into liquid. Finally, the new helium liquid is piped into a giant storage tank and then transferred into wheeled delivery containers, ready for the next experiments. The helium liquefier, built by Linde, condenses 15-17 liquid liters of helium per hour.

“I think when you look at the workmanship of that facility, I would say it is second to none,” said Smith, who likened Shafer's engineering to ‘Swiss craftsmanship'. “We did a lot of the installation ourselves, via our shop guys. This was crucial for the success of the facility.”

Smith and Dewald expressed interest in eventually partnering with nearby hospitals, which also use helium for some equipment. The helium liquefier will be shown along with the Department of Physics and Astronomy's other facilities and labs at its Open House on November 5.