Completion of DFX and DFM cryostats for the HiLumi LHC Cold Powering Systems
By Amalia Ballarino (CERN)
In January 2026, CERN and the University of Southampton (SOTON) celebrated the successful completion of the series production of the DFX and DFH cryostats for the High-Luminosity LHC (HiLumi LHC) Cold Powering Systems.
Two types of complex cryostat units, DFX and DFM, with ten units in total (eight plus two spares) were produced in UK industry under the coordination and supervision of SOTON, within the framework of the HiLumi LHC UK2 Collaboration Agreement, signed in 2022.
These cryostats, featuring a high level of integration with both the system architecture and the LHC tunnel, operate at 4.5 K. Each receives the magnesium diboride (MgB₂) cables from its respective Superconducting Link and provides the connection to the 1.9 K superfluid helium environment of the magnets in the tunnel, allowing the current from the Superconducting Link to supply the magnet chain (see figure 2).
The series production was well aligned with the schedule of HiLumi LHC Work Package 6A (responsible for the Cold Powering Systems). The first DFX unit is now part of the Cold Powering System operated in the IT String, and the second DFX and first DFM units are used for surface testing of the Cold Powering Systems. The remaining series units will be installed underground in the HiLumi LHC during Long Shutdown 3.
The completion of this agreement marks the conclusion of a highly collaborative and successful effort, driven by strong team spirit and close collaboration, in which knowledge and expertise were shared in pursuit of a common goal. This milestone also marked the end of all collaboration and procurement activities for Work Package 6A.
