Heat Transfer from Insulated Rutherford Type Cables Immersed in Pressurized He II

The heat load on a high field accelerator superconducting magnet induced by beam losses is a major subject to be solved for stable operation of the Large Hadron Collider (LHC) magnets. The maximum beam loss in an insertion quadrupole magnet has been estimated to be a level of 104 W/m3. While heating the coils to cure the epoxy resin, it will flow into gap between layers of the electrical insulation. Effects of epoxy resin permeating into the electrical insulation and the space (void) between cable strands on cooling have been studied under various conditions. A new measurement is devised to comprehend the heat transfer characteristics by using a cable that has a composite structure identical to the real one. Results of measurements on the heat transfer characteristics for several types of insulation are presented and discussed in this paper.