Irradiation response of next generation high temperature superconductors for fusion energy applications

The latest generations of rare-earth substituted and nano-doped YBa ₂Cu₃O_7-x (YBCO) high temperature superconductors (HTS) developed for applications in magnetic fields are being evaluated for potential use in fusion energy applications. The benefits include increased plasma performance and reduced system cost through more compact and cryoplant-free fusion energy systems. The response to ion irradiation of commercially produced GdBa₂Cu₃O_7-x, (Y,Dy)Ba₂Cu₃O_7-x, and Zr-doped (Y,Gd)Ba ₂Cu₃O_7-x samples was investigated. These stateof- the-art conductors represent different design methods for enhanced flux pinning, resulting in different responses to radiation damage. Irradiations using 5-MeV Ni and 25-MeV Au ions were used to examine cascade damage while keeping electronic energy loss levels below columnar defect thresholds. An improved radiation tolerance is found in these new generation HTS conductors. Specifically, the influences of irradiation on the superconducting critical temperatures and the electrical transport properties of the samples were much less than that observed on the earlier generation of irradiated HTS materials investigated by others.