Extending the Application of HTS in Particle Accelerators

The year-to-year improvements in the characteristics of high temperature superconductor (HTS) materials encourage periodic reappraisal of their applicability for use in accelerators. With the successful large-scale application of HTS technology for the current leads of the Large Hadron Collider at CERN, this tendency is accentuated, and the new materials are now starting to receive more serious attention as candidates for other accelerator-related applications. The medium- to long-term goal will be to use the materials for magnets, but their characteristics are totally different from those of classical multi-filamentary Nb-Ti material and the transition will be difficult. In particular it seems likely to be inappropriate to carry over the presently conventional coil geometries and conductor excitation levels. A roadmap is proposed for R&D that will lead progressively to achieving the ultimate goal through consolidation of the necessary technology via intermediate steps, and progressive accumulation of successful applications.