Superconducting Coil Compression by Scissor Laminations

A new system of coil compression has been designed which uses iron laminations to transfer the pressure from an outer shrink ring to the coil. The laminations are simple circular discs around the coil with the peculiarity that the rim is slightly eccentric as compared to the coil. Successive laminations are mounted with different angular orientations to oppose their eccentricities. The shrink ring pushed these discs inwards against the coil creating compression by a scissor movement. Tests on mechanical models of single as well as multiple aperture magnets have shown it to work as expected. The system has already successfully been applied to several corrector magnets for LHC. The advantages are low cost (suppression of the usual collars), increased coil compression in particular from cooling down, and field enhancement from having the iron close to the coil.