Cable insulation serves multiple key functions in Nb3Sn superconducting magnets. Beyond preventing turn-to-turn arcs during quenches, it reduces cracking in the coil’s epoxy resin matrix, and ensures a thin, well-defined spacing between coil turns to maximise current density and control conductor positioning for field quality. It is designed for compatibility with the Nb3Sn reaction heat treatment, subsequent epoxy impregnation and the demanding operating conditions of the magnets.
This seminar analyses thermal and plasma treatments aimed at increasing the dielectric strength and longevity of the cable insulation. First, the mechanism of electrical insulation is discussed, with an emphasis on the role of glass-fibre sizing. This is followed by a summary of the different treatments applied at CERN and other institutes, and their results in improving electrical insulation performance. The seminar concludes with a review of the benefits, challenges and potential implementation of thermal and plasma treatments in magnet coil fabrication for high-field magnets.