Since the last newsletter in June 2024, the interaction region (IR) magnets for the HL-LHC have reached several key milestones. One of the most significant achievements was the delivery of all cryo-assemblies to the IT String, including the DCM connection module, marking a major step forward in the integration process. With Work Package 3 now in full production mode, the focus is on meeting the tight deadlines required for installation during Long Shutdown 3. Significant progress has been made on all fronts, thanks to the truly collaborative effort involving teams from around the world. We are all in the same boat — working together to ensure that every single component is ready on time and adhering to the acceptance criteria for reliable operation in the IT String and LHC tunnel.
Figure 1. Completed magnet line of the IT String. Florence Thompson / CERN
Q2 triplet magnets – CERN
The series production of the MQXFB triplet magnets is advancing steadily. Since the last newsletter, two additional magnets — MQXFB05 and MQXFB06 — have been successfully qualified, bringing the total to four out of the eight magnets required for the HL-LHC installation. The improvements introduced in the fabrication process have proven effective in addressing the issues identified in the prototypes. These enhancements are now validated through the consistent quality and performance of the more recent units, providing confidence as the project moves closer to installation
Production continues at the nominal rate of one coil per month, 3-4 magnets per year: testing of MQXFB07 is underway, MQXFB08 is being prepared for testing, cold mass production for MQXFB09 is ongoing, and assembly of MQXFB10 is in progress. In parallel, coil production for the final two magnets (designated as spares) is ongoing, with the winding of the last coil expected to be completed by the end of 2025.
Figure 2. MQXFB coil fabrication team. Susana Izquierdo Bermúdez / CERN
Q1 and Q3 triplet magnets – US-AUP collaboration
In January 2025, the second cryo-assembly from US-AUP was successfully delivered to CERN and is now installed in the IT String, completing the IT String magnet line.
Testing of the third cryo-assembly is currently underway at Fermi National Accelerator Laboratory (FNAL), while the fourth and fifth cryo-assemblies are nearing completion. These will undergo qualification tests at CERN before installation in LS3.
Since June 2024, five magnets have been qualified through vertical testing at Brookhaven National Laboratory (BNL): MQXFA13b, MQXFA18, MQXFA12b, MQXFA17b, and MQXFA19. One magnet, MQXFA16, was limited by a coil and did not reach nominal current. Out of the twenty magnets required for the project – sixteen for installation plus four spares – fifteen have now been successfully qualified through vertical testing.
Figure 3. First (right) US-AUP cryo-assembly in the IT String, whilst the second (left) is being installed. Melanie Arnold, Maximilien Brice / CERN
Nested orbit correctors – CIEMAT collaboration
Due to delays with the original industrial partner, production of the nested dipole orbit corrector magnets was reorganised: coil winding is now handled by CIEMAT in Spain, while magnet assembly takes place at CERN. The new production lines are fully operational, and progress is back on track.
Four additional magnets (MCBXFA1, MCBXFB06, MCBXFB07, and MCBXFA2) have been successfully qualified in the last twelve months. A fifth magnet, MCBXFB08, has recently been completed and will soon undergo cold testing to verify its performance. Looking ahead, five more magnets remain to be produced to complete the series. These are expected to be completed by summer 2026.
Figure 4. CIEMAT-CERN team for the fabrication of MCBXF magnets, together with the first magnets built after internalisation of the assembly process. Mike Struik / CERN
D1 separation dipoles – KEK Collaboration
All four D1 magnets required for HL-LHC installation have now been fully qualified through vertical testing. The first series cold mass, MBXF1, was delivered to CERN at the end of 2024 and is now ready for horizontal testing in its final configuration. The cold mass for the second magnet is nearing completion and is expected to arrive at CERN after the summer. Construction of the remaining cold masses, along with two spare magnets, is ongoing in Japan with the support of the industrial partner Hitachi.
Figure 5. Training of MBXF prototype and series magnets. CERN
D2 – INFN, Genoa collaboration
The series production of the D2 separation dipoles is progressing. Both the first and second magnets, MBRD1 and MBRD2, have been integrated into their respective cold masses. MBRD2 is currently undergoing testing, while cryostating activities for MBRD1 are underway in preparation for its test later this year.
MBRD3 has been completed, however a non-conformity was identified and is currently being addressed at ASG, Genoa. The fourth magnet, MBRD4, has been delivered to CERN, and integration into the cold mass will begin shortly. Meanwhile, the collaring of the fifth series magnet, MBRD5, is in progress. In total, six magnets need to be produced (four for installation and two spares).
Figure 6. Production of D2 magnets at ASG (Italy). MBRD3 in its transport frame (left), MBRD4 magnet being completed (middle), first collared coil of MBRD3 (right). ASG