Cryocooler cools an accelerator cavity
(PHYSorg.com Physics)

Particle accelerators are made of structures called cavities, which impart energy to the particle beam, kicking it forward. One type of cavity is the superconducting radio-frequency, or SRF, cavity. Usually made of niobium, SRF cavities require extreme cold to operate. A Fermilab team developed a new way of cooling SRF cavities without liquid helium. The new system is easier to operate and simpler to construct.