Momentum is gathering behind the High-Luminosity LHC (HL-LHC) project. In laboratories on either side of the Atlantic, a host of tests are being carried out on the various magnet models.

In mid-March, a short prototype of the quadrupole magnet underwent its first testing phase at the Fermilab laboratory in the United States. This magnet is a pre-prototype of the quadrupole magnets that will be installed near to the ATLAS and CMS detectors to squeeze the beams before collisions. Six quadrupole magnets will be installed on each side of each experiment, giving a total of 24 magnets, and will replace the LHC's triplet magnets. Made of superconducting niobium-tin, the magnets will be more powerful than their predecessors, which will result in an increase in the LHC's luminosity, or in other words the probability of collisions. The HL-LHC will produce a luminosity level ten times greater than at the LHC today.

The magnet tested at Fermilab consists of two coils manufactured at CERN and two others manufactured by the LARP (LHC Accelerator Research Program) consortium, which comprises four US laboratories. “The construction of this prototype is the product of a real international effort,” emphasises Lucio Rossi, the HL-LHC project leader.

The prototype is 1.5 metres long, whereas the final magnets will be 4.2 or 7.15 metres long. During the tests, a peak in the magnetic field of 12.5 tesla was measured on the coils, compared to 8 tesla for the LHC’s current quadrupole magnets, an impressive achievement. The tests will continue, while in parallel a second short prototype is being built and will be tested later in the year.

“We will also start manufacturing actual-size prototypes, i.e. 7.15 metres for the CERN design and 4.2 metres for the LARP design," explains Ezio Todesco, who is in charge of the insertion region magnets for the HL-LHC project. These prototypes will be ready for testing in 2017.