The Low-Beta Quadrupoles for the High-Luminosity Large Hadron Collider: enabling higher luminosity by using Nb₃Sn conductor

The large-aperture, high-gradient Low Beta Quadrupoles for the High-Luminosity Large Hadron Collider at CERN are the cornerstones of this collider. They are first-of-the-kind accelerator magnets bringing Nb₃Sn conductor to High Energy Physics colliders.

In the US they are being fabricated and tested by the LHC Accelerator Upgrade Project (AUP), and in Europe by CERN. The design was developed by AUP and CERN in close collaboration. The Q1/Q3 cryo-assemblies contain two 4.2 m long magnets (MQXFA) fabricated and by AUP. The bare MQXFA magnets are tested vertically before use in a cry-assembly.

In this paper we are going to present the main features of the MQXFA design, results of vertical tests, and main lessons learned. We will also discuss lessons learned for future use of Nb₃Sn magnets in HEP colliders.