Fabrication of the 7.3-m-Long Coils for the Prototype of MQXFB, the Nb3Sn Low-b Quadrupole Magnet for the HiLumi LHC

The high-luminosity LHC upgrade target is to increase the integrated luminosity by a factor of 10, resulting in an integrated luminosity of 3000 fb
^-1
. One major improvement foreseen is the reduction of the beam size at the collision points. This requires the development of 150-mm single aperture quadrupoles for the interaction regions. These quadrupoles are under development in a joint collaboration between CERN and the US-LHC Accelerator Research Program. The chosen approach for achieving a nominal quadrupole field gradient of 132.6 T/m is based on the Nb
₃
Sn technology. The coils with a length of 7281 mm will be the longest Nb
₃
Sn coils fabricated so far for accelerator magnets. The production of the long coils was launched in 2016 based on practice coils made from copper. This paper provides a status of the production of the first low grade and full performance coils and describes the production process and applied quality control. Furthermore, an outlook for the prototype assembly is provided.