Final series production D1 magnet for the HL-LHC has arrived at KEK

2026-08-21 2026-08-21

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The High-Luminosity Upgrade for the Large Hadron Collider (High-Luminosity LHC, HL-LHC) is currently progressing under the leadership of the European Organization for Nuclear Research (CERN). As part of Japan's contribution to this project, the Cryogenics Science Center is responsible for developing the beam separation superconducting dipole magnets (D1 magnet, MBXF). Previous efforts have been featured in past highlight articles and IPNS Topics [1]-[5]. These magnets are installed on both sides of the two interaction points of the LHC (ATLAS and CMS). Their function is to align the two opposing beams on the same orbit towards the interaction point and to separate the beams after they pass through the interaction points. The coils are fabricated with Nb-Ti superconducting cables. The magnets have a cylindrical shape with an outer diameter of 570 mm and a length of 7 m. Their weight is 12 tons. The main dipole field is 5.6 T within an aperture of 150 mm. One prototype and six production cold masses will be constructed by a Japanese manufacturer and shipped to CERN.
During the manufacturing process, the D1 magnets are transported to KEK for performance evaluation tests. The final D1 magnet arrived at KEK at the end of June, 2026. Figure 1 shows the magnet being lifted up for insertion into the 9 m-deep vertical cryostat in Cryogenics Building No.4. After the magnet is cooled down to 1.9 K (-271℃), excitation tests up to 13230 A and measurements of magnetic field quality will be conducted. For the past five magnets, the acceptable performance satisfying the required specifications has been confirmed.

Fig. 1 Series production D1 magnet No. 6 being lifted up for insertion into the vertical cryostat

Categories: Cryogenics Science Center and Highlight

Young Investigator Presentation Award Received at the 63rd Annual Meeting on Radioisotopes and Radiation Researches