Assembly of the Nb3Sn Dipole Magnet FRESCA2

The Nb3Sn dipole magnet FRESCA2 has been developed and manufactured within the framework of a collaboration between the Centre for Atomic Energy (CEA Saclay) and the European Organization for Nuclear Research (CERN). The aim of the magnet is to upgrade the superconducting cable test station at CERN with a Nb3Sn dipole providing a 13-T magnetic field in a 100-mm aperture. The magnet is composed of four coils in a block-type configuration with flared ends, 1.6 m long, housed in a bladder, and key-type mechanical structure. A first assembly of the magnet, FRESCA2a, has been done at CERN at the end of 2016 with the four first Nb3Sn coils fabricated at CEA Saclay and CERN. The coils were dimensionally measured, and tailored shims were fabricated and inserted in the coil pack to improve the contact between layers. In addition, tests with pressure sensitive films were carried out to verify the uniformity of the loading. The magnet was cold tested in February 2017 and dismounted to replace one coil. A second assembly, FRESCA2b, was produced and tested in August 2017. In this paper, we provide a detailed description of the various steps of the assembly from the impregnated coils to the delivery of the dipole to the test facility, with a particular emphasis on the procedures followed and the tooling developed.