Construction of a 56 mm aperture high-field twin-aperture superconducting dipole model magnet

A twin-aperture superconducting dipole model has been designed in collaboration with Finnish and Swedish Scientific Institutions within the framework of the LHC R&D programme and has been built at CERN. Principal features of the magnet are 56 mm aperture, separate stainless steel collared coils, yoke closed after assembly at room temperature, and longitudinal prestressing of the coil ends. This paper recalls the main dipole design characteristics and presents some details of its fabrication including geometrical and mechanical measurements of the collared coil assembly.