CERN and LHC-AUP developing quadrupole magnets

The Large Hadron Collider (LHC) is set to be upgraded to the High-Luminosity LHC and this will require over one kilometre of the machine needing to be replaced, recently discussed.
Installation isn’t set to begin until 2024 but scientists and engineers around the world are already starting to develop the new magnets that will be needed for the upgrade.
It is estimated that the new machine will require around 100 magnets of 11 new types, consisting of: four types of main magnets (dipole and quadrupole which are designed to bend and focus the beams); and seven different types of correcting magnets.

Using innovative technology, the main quadrupole magnets will provide fields beyond 10 Tesla. These are being developed under a collaboration between CERN and the LHC-AUP (LHC Accelerator Upgrade Project) consortium.

The collaboration will involve three US laboratories and will see two types of these new magnets developed in two different lengths – 4.5m in the US and 7.5m at CERN.

As the design phase is completed, the main magnets are in the prototype phase. However, tests assessing the stability of the design and mechanical structure are being conducted on shorter models (1.5m) because of the high cost of the magnets’ materials.

Initial tests in the US, involving a short model quadrupole made of two coils from the LARP (LHC Accelerator Programme) consortium and two from CERN, reached a peak magnetic field of 13 T. CERN conducted another test on a short model, with three CERN coils and one made in the US, where a peak field of 12.2 T was measured.

Another iteration of the assembly will take place in the second half of this year, while CERN is set to soon test a third short model, which will be the first one with a homogenous set of coils.

A full-length 4.5-metre-long coil was tested at the US Brookhaven National Laboratory in January this year. It reached the nominal field value of 13.4 T.

CERN has already begun winding the 7.15-metre-long coils at its Large Magnet Facility building.

Ezio Todesco, a physicist in the SC Magnet Design and Technology section in the Magnets, Superconductors and Cryostats group of the Technology department, and leader of the work for the HL-LHC project dealing with magnets for the insertion regions, explained that they will be testing the first full-length prototypes between the end of this year and the end of 2018.

He added: “We will have then the confirmation that they perform as expected, and see whether some design iteration is needed.”