Serial installation of Cryomodules starts at ESS

CM installation
Double-cavity spoke cryomodule under installation and alignment in the ESS Accelerator tunnel. Image: Ulrika Hammarlund/ESS

As of 7 August, ESS has started the serial installation of cryomodules in the superconducting part of the linear accelerator. This marks a crucial step forward in the construction of the ESS accelerator, aligning with the overarching objective of achieving Beam on Target (BOT) by 2025.

Insights gained from the previous pilot installation of two cryomodules have paved the way for an efficient process with well-defined procedures.

Facility layout - Accelerator

ESS facility outline, with the Accelerator buildings marked in blue.


The installation of cryomodules for the spoke section of the ESS superconducting linac started as planned. To date, four double-cavity spoke cryomodules have been rolled into the accelerator tunnel and positioned in their designated permanent locations. The process of aligning and connecting these cryomodules is currently underway.

All 13 cryomodules for the spoke section are the in-kind contribution by IJC Lab in France.

B02 Spoke CMs

The remaining double-cavity cryomodules are being prepared for installation in the ESS on-site workshop.

Image: Ulrika Hammarlund/ESS

Prior to their on-site installation, the cryomodules underwent pre-testing and cooldown at Uppsala University’s Freia lab. Furthermore, the modules are being prepared at the on-site workshop by a collaborative effort led by ESS Superconducting Radio Frequency (SRF) team with the support from ESS rigging, alignment and vacuum teams. In-kind partners IFJ PAN (Poland) and IJC Lab (France) as well as ESS contractor PowerHeat are also involved in the preparation process.

CM welding

Process pipes from the cryomodule are welded to the valvebox of the cryogenic distribution system.

Image: Henry Przybilski/ESS

A key aspect of this installation involves welding of process pipe extension cups, tailored for each specific position, connecting the cryomodules to their respective valveboxes within the cryogenic distribution system.

The ongoing installation process builds upon valuable insights gained from a pilot study conducted between March and June of 2023. During this pilot study, two cryomodules, one for the spoke and one for the medium beta section, were successfully cooled down to the target temperature of 2 Kelvin as part of the second cooldown of the Cryogenic Distribution System at ESS. These learnings have been instrumental in refining procedures, streamlining processes, and accelerating the overall installation timeline.

The installation in the tunnel will continue until all 13 spoke cryomodules are in place and connected to the RF system on the gallery side.

Later this autumn, the installation of the medium and high beta cryomodules - needed for Beam On Target - will follow.


Schematic layout Accelerator

Schematic view of the ESS linac, with the cryomodules required for Beam on Target marked in blue.

Ciprian Plostinar/ESS

Short video clip from the cryomodule installation in the ESS Accelerator tunnel.

Videography: Ulrika Hammarlund/ESS




ESS Road to Science (label)