Cryomodule Test Facility fridge cool on many levels

A drawing of the complex built near the New Muon Lab (left). The Cryomodule Test Facility, in the background, will house the CMTF refrigerator.

Flexibility isn’t usually the first thing you look for in a refrigerator.

But Fermilab’s future Cryomodule Test Facility (CMTF) refrigerator, recently approved for construction by DOE, is being designed as a one-size-fits-many cryogenic plant for the laboratory’s future superconducting radio-frequency research projects.

“Versatility is the prime objective of the new cryoplant,” said Arkadiy Klebaner, technical manager for the CMTF refrigerator project.

It will use superfluid helium to cool SRF cavities to 1.8 Kelvin while providing a variety of thermal shields by flowing helium at just the right temperatures.

As a bonus, it will also be several times more energy efficient than any superfluid helium cryogenic system currently in operation at the laboratory.

The key is the hybrid design of the pumping system, which uses both warm and cold pumping cycles to cool helium.

Fermilab’s current systems use only warm pumping, which brings ultra-cold liquid helium back up to ambient temperature before re-cooling it as it’s cycled through the experiment.

With the addition of cold pumping, the CMTF refrigerator can recycle cold helium without first warming it, so less energy is required to cool it back down. The hybrid cycle also allows it to pump helium through a wide range of operational loads.

Combining the old with the new, the design also incorporates the Tevatron’s compressors and storage tanks, reengineered to cool helium to 1.8 Kelvin.

Custom made for Fermilab’s SRF facilities, the refrigerator will serve as a cryogenics training ground for technicians and engineers.

“We’re excited for the fulfillment of a project that’s the result of the shared vision and effort of many people over the last eight years,” Klebaner said.

The CMTF refrigerator will be commissioned in the spring of 2013.

–Leah Hesla