CERN: Keeping Helium in the Loop

Cold magnets, energetic particles

CERN’s Large Hadron Collider uses superconducting magnets to guide and focus particle beams. Its cryogenic system uses helium, including superfluid helium at about 1.9 kelvin, to maintain the required low temperatures. Helium provides cooling; it is not the beam fuel [S17].

A 2026 maintenance example

In an August 5, 2026 account of the LHC warm-up, CERN described removing helium from the magnets and cryogenic distribution line after electrical isolation. Heaters evaporated the liquid helium; the gas was sent to the surface, liquefied and stored for reuse [S118].

That account illustrates an important distinction: warming a machine does not require deliberately discarding its helium. The article’s completion and restart dates were plans at publication, not a confirmation here that later milestones occurred.

Inventory is different from loss

The amount held in an installation is not the amount lost each year. Likewise, transferring helium into storage is not consumption. To evaluate conservation, ask for the defined system boundary, make-up purchases, transfers, venting and measured losses over a stated period.

Compare CERN’s example with Boulder’s helium recovery work and use the inventory worksheet to frame the questions.

Sources and further reading

• Cryogenics: low temperatures, high performance — CERN [S17].
• The LHC is being warmed up from near absolute zero to room temperature — CERN [S118].

Reviewed October 24, 2026. Read our sources and methods and review and update record.