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As part of the High-Luminosity upgrade project (HL-LHC) for the Large Hadron Collider (LHC) at CERN, new double-aperture beam orbit corrector magnets will be installed near the recombination dipole (D2). These magnets are 2.2 m long Nb–Ti dipoles based on the Canted Cosine-Theta (CCT) design. They provide an in bore magnetic field of 2.60 T at 394 A in a 105 mm aperture with an integrated field of 5 Tm. The fourth full-length prototype was built and tested at CERN. Its design is based on the best engineering practices from previous prototypes. In this paper we first report on recent improvements in the manufacturing process, focusing on the feedback from winding and on the optimization of the impregnation phase. The magnetic measurements carried out at warm and cold temperatures are then reported. Finally, the results of powering tests at 1.9 K and 4.5 K are presented. The magnet meets the dimensional, electrical and magnetic requirements, and is a valid reference for the HL-LHC series production that is currently being carried out in collaboration between CERN and Institute of High Energy Physics (IHEP).

Due to its flexibility in generating advanced field harmonic corrections and potential for low cost compared to traditional designs, the Canted Cosine Theta (CCT) configuration is particularly interesting for compact particle accelerators and gantries for medical applications. This article presents the design of a curved demonstrator named Fusillo, a Canted Cosine Theta Nb-Ti dipole magnet that is being developed at CERN, featuring a large aperture of 236 mm, a small bending radius of 1 m, a bending angle of 90$^{\circ }$, and multi-harmonic field correction, with a 3.61 T conductor peak field. We detail the magnetic coil design, incorporating high-order magnetic field correction of the errors produced by the heavily curved coil, peak field reduction at the coil ends, the development of a new rope type cable, and the mechanical design and the development of the former that supports the coil and provides the curved shape. We also present the first results of a subscale model used to qualify the coil's former manufacturing process, the rope cable, the coil winding optimization, and the coil impregnation system.