Engineering design and fabrication of the nested orbit corrector prototype for HL-LHC

MCBXF magnets are nested orbit correctors, needed for the upgrade of the large hadron collider (LHC), in the framework of the high luminosity (HL) LHC project. There are two versions with different physical lengths, 1.5 and 2.5 m, which share the same cross section to decrease fabrication costs. These magnets have a large aperture of 150 mm and due to the high radiation dose, a mechanical clamping is necessary to hold the large torque between both dipoles. Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas CIEMAT is developing the short MCBXFB prototype in collaboration with CERN. This paper describes the engineering design of the magnet, which is based on previous magnetic and mechanical calculations. The axial pre-stress on the coil ends is analyzed in detail. Some innovative techniques have been developed for the coil fabrication because of the high number of turns and large aperture.