Insulation development for the Next European Dipole

The Next European Dipole (NED) Consortium is working to develop the technology of high field, dipole magnets for a future luminosity upgrade of the LHC at CERN. The proposed magnet will be a large aperture (88 mm), high field (15 T) superconducting dipole using Nb3Sn Rutherford cable and a wind-and-react manufacturing scheme. The magnet scale, forces and manufacturing route present real challenges for the conductor insulation technology. This paper reports on the insulation R&D programs carried out during the first phase of the NED project (2004 to 2007). In the R&D programs both conventional, (glass fiber-polymeric matrix) and innovative (ceramic) insulation materials have been studied. A primary objective was to develop a working insulation specification for a dipole magnet at the NED scale. Specialized sample geometries and test methods (mechanical and electrical) have been developed to make comparison between different insulation materials and processing routes. In particular, the role of sizing on glass fiber insulation subjected to Nb3Sn magnet processing parameters has been studied using thermo gravimetric analysis.