Irradiation imposed degradation of the mechanical and electrical properties of electrical insulation for future accelerator magnets

Future accelerators will make extensive use of superconductors made of Nb3Sn, which allows higher magnetic fields than NbTi. However, the wind-and-react technology of Nb3Sn superconducting magnet production makes polyimide Kapton® non applicable for the coils' electrical insulation. A Nb3Sn technology compatible insulation material should be characterized by high radiation resistivity, good thermal conductivity, and excellent mechanical properties. Candidate materials for the electrical insulation of future accelerator's magnet coils have to be radiation certified with respect to potential degradation of their electrical, thermal, and mechanical properties. This contribution presents procedures and results of tests of the electrical and mechanical properties of DGEBA epoxy + D400 hardener, which is one of the candidates for the electrical insulation of future magnets. Two test sample types have been used to determine the material degradation due to irradiation: a untreated one (unirradiated) and irradiated at 77 K with 11 kGy/min intense, 4MeV energy electrons beam to a total dose of 50 MGy.