Nb3Sn SRF cavity development at Fermilab

Abstract:  Nb3Sn is a promising future material for superconducting radiofrequency (SRF) cavities. It requires R&D to develop fully for applications, but it already shows high Q0 at relatively high temperatures including near 4 K, and predictions suggest that its ultimate accelerating gradient limit would be significantly higher than that of niobium. Fermilab recently started a Nb3Sn SRF cavity development program, with the goals of pushing performance and scaling up from R&D-style cavities to production-style cavities. In this presentation, I overview the coating process, parameter exploration to achieve high quality films, single-cell 1.3 GHz cavity performance, and first exploration of cavities beyond 1.3 GHz single cells.