Title: Multilayer Approach to Increase the Performance of SRF Accelerating Structures beyond Bulk Nb
Author: Anne-Marie Valente-Feliciano
Abstract: A-M. Valente-Feliciano, D. Beringer, G. Eremeev, R. A. Lukaszew, L. Phillips, C. Reece, J. K. Spradlin
For the past three decades, bulk niobium has been the material of choice for SRF cavities applications. RF cavity performance is now approaching the theoretical limit for bulk niobium. For further improvement of RF cavity performance for future accelerator projects, Superconductor-Insulator-Superconductor (SIS) multilayer structures (as proposed by Alex Gurevich) present the theoretical prospect to reach RF performance beyond bulk Nb, using thinly layered higher-Tc superconductors with enhanced Hc1. Jefferson Lab (JLab) is pursuing this approach with the development of NbTiN and AlN based multilayer SIS structures via magnetron sputtering and High Power Impulse Magnetron Sputtering (HiPIMS). This contribution presents the characterization of NbTiN and insulator films and some RF measurements on NbTiN-based multilayer structures.