P. Abramian

This paper describes the design and fabrication of four sets of HTc 600 A current leads manufactured by ANTEC in collaboration with three more Institutes to test the feasibility of industrial fabrication of these units. This development has been made in the framework of a CERN programme to build low thermal losses leads for the correction magnets of the LHC. Tests performed at the manufacturer installations are also presented.

The high luminosity upgrade will enhance the discovery potential of the LHC in the next decade. Among other magnets and technologies currently under development, the MCBXF orbit correctors will be required to this end. In order to save space, they consist in two perpendicularly and coaxially arranged dipole coils under a large torque. Coils cannot be glued due to the high radiation dose expected, and mechanical clamping is mandatory. With the goal of turning the conceptual design into a tangible reality, this paper depicts the final magnetic design, with special attention to 3-D electromagnetic calculations and the different operation scenarios. It also includes more accurate mechanical FE models results, achieved by measuring the Young's modulus of impregnated cable stacks. Besides assembly spring-back, cool-down, and energization, simulations have been also carried out for the pressing process of both dipoles, analysing stress distribution, and displacements. Finally, a short mechanical model has been designed, fabricated, and tested. Its main purpose is to assess the feasibility of the proposed clamping structure, the reliability of the FE mechanical models and the design of an important part of the tooling required for the magnet fabrication.

Two prototype superconducting corrector magnets, a sextupole and an octupole, have been designed and fabricated by CIEMAT during the preparatory phase for the Large Hadron Collider (LHC) luminosity upgrade, in the framework of the SLHC project. These magnets will be grouped with other correctors in a dedicated cryo-assembly, placed in the LHC insertion regions. The magnets shall be designed to withstand radiation levels up to 10 MGy. Therefore, the nominal aperture will be increased to 140 mm to include a 10-mm-thick steel shielding, and all materials must be radiation resistant. The sextupole has been produced with conventional materials but radiation-resistant ones have been used for the octupole, like polyimide insulated wire and cyanate-ester resin. The nominal integrated strength of the sextupole is 0.055 T · m (0.035 T · m for the octupole) at 40 mm reference radius and overall mechanical length is 160 mm (180 mm for octupole). Due to the moderate peak field, a superferric design is preferred, which also allows placing the coils further away from the aperture. Fabrication techniques and test results are described.

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.