For the first time, a superconducting radio-frequency cavity has been cooled and operated using cryogenic refrigerators

For the first time, a team at Fermilab has cooled and operated a superconducting radio-frequency cavity — a crucial component of superconducting particle accelerators using cryogenic refrigerators — with cryocoolers, breaking the tradition of cooling cavities by immersing them in a bath of liquid helium. It achieved an accelerating gradient of 6.6 million volts per meter.

This new method — based on a Fermilab idea patented five years ago — uses cryogenic refrigerators, or cryocoolers, for removing the heat dissipated by a superconducting accelerator cavity. By compressing and expanding helium gas across a regenerative heat exchanger in a “closed” cycle, the cryocoolers produce cooling without letting the helium out. This closed-cycle operation of cryocoolers makes the system very compact — more so than the standard liquid helium cooling equipment used by traditional accelerator cavities.

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