Dresden 2026 – scientific programme
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DS: Fachverband Dünne Schichten
DS 20: Poster
DS 20.22: Poster
Thursday, March 12, 2026, 18:30–20:30, P2
Investigations of point defects in Nb3Sn thin films for SRF application — •Sebastian Klug1, Maik Butterling2, Eric Hirschmann1, Andreas Wagner1, and Maciej Oskar Liedke1 — 1Institute of Radiation Physics, HZDR, Germany — 2Reactor Institute Delft, Delft University of Technology, The Netherlands
Bulk Niobium cavities are the state-of-the-art option to realizes high-performing linear particle accelerators. To achieve even better performance and lowering operational costs, a thin film approach with different superconducting materials is necessary. Nb3Sn coatings are promising candidates because of its high superconducting transition temperature (Tc up to 17 K). Magnetron sputtering is a very suited PVD method which provides high deposition rates and a large spectrum of deposition parameters optimization. Maximizing the transition temperature and the lower critical magnetic field Hc1 could be correlated to the structure and point defects in thin films like vacancies, their agglomerations and pores. To study this effect, positron annihilation spectroscopy (PAS) with a high sensitivity to small void-like defects is used. PAS provides non-destructive and depth-resolved information of defect type, size and density as well as their local atomic chemistry in many material types like metals, polymers, ceramics and semiconductors. In this contribution, investigations on magnetron sputtered Nb3Sn thin film samples will be presented. A special focus is set to positron annihilation spectroscopy to study the influence of different deposition parameters on defect formation and the resulting superconducting performance.
Keywords: Superconductivity; SRF Cavity; Thin films; Magnetron sputtering; Positron annihilation spectroscopy