Progress on the Development of the Nb3Sn 11T Dipole for the High Luminosity Upgrade of LHC

Abstract

Abstract-The High Luminosity LHC Project at CERN entered into the production phase in October 2015 after the completion of the design study phase. In the meantime, the development of the 11 T dipole needed for the upgrade of the collimation system of the machine made significant progress with very good performance of the first two-in-one magnet model of 2-m length made at CERN. The 11 T dipole, which is more powerful than the current main dipoles of LHC, can be made shorter with an equivalent integrated field. This will allow creating space for the installation of additional collimators in specific locations of the dispersion suppressor regions. Following tests carried out during heavy ions runs of LHC in the end of 2015, and a more recent review of the project budget, the installation plan for the 11 T dipole was revised. Consequently, one 11 T dipole full assembly containing two 11 T dipoles of 5.5-m length will be installed on either side of interaction point 7. These two units shall be installed during the long shutdown 2 in years 2019-2020. After a brief reminder on the design features of the magnet, this paper describes the current status of the development activities, in particular the short model programme and the construction of the first full scale prototype at CERN. Critical operations like the reaction treatment and the coil impregnation are discussed, the quench performance tests results of the two-in-one model are reviewed and finally, the plan towards the production for the long shut downs 2 is described.  Index Terms-Accelerator magnets, high-luminosity large hadron collider (LHC) project, Nb3Sn 11 T dipole, superconducting magnets.

Nb3Sn 11 T Dipole for the High Luminosity LHC (CERN)

“…The single-and two-in-one-aperture structures developed at CERN for the 11 T dipole (Savary et al 2017) are shown in Fig. 9.9.…”

Applied Metrology in the Production of Superconducting Model Magnets for Particle Accelerators

“…Nowadays, the new LHC luminosity upgrade [3], [4] has required the development of two new superconducting magnets wound with Nb3Sn superconductor: the 11 T dipole for the arcs [5] and the MQXF quadrupole for the insertion regions [6]. These two projects are already well advanced in the prototyping phase, after having gone through a short model development program [7], [8]. At the moment of writing this paper, a total of 17 model coils have been produced for each of the projects.…”

Nb3Sn Accelerator Dipole Magnet Needs for a Future Circular Collider

“…With respect to the LHC, this quest for a doubling of the field requires a change of superconducting material, because the upper critical field B c2 of Nb-Ti at 1.9 K is limited to, at most, 13.5 T (Bottura 2000), limiting the ultimate field amplitude of Nb-Ti accelerator magnets to about 10 T. A field level of 16 T is also 5 T higher than the field in the Nb 3 Sn magnets currently being developed for the High Luminosity LHC (HL-LHC or Hi-Lumi LHC) Savary et al 2017). Once installed, they will be the first high-field Nb 3 Sn magnets ever operated in a particle collider.…”