Title: RF and structural characterization of SRF thin films produced by energetic condensation
Author: AnneMarie Valente
Institution: Jefferson Lab – Newport News (VA) USA
Abstract: In the past years, energetic vacuum deposition methods have been developed in different laboratories to further improve thin film technology for superconducting cavities. Energetic condensation produces high density plasma with singly or quasi-singly charged ions and allows growth modes that favour a better structure and performance in thin films. In the framework of a collaboration with surrounding universities, JLab is pursuing energetic condensation deposition particularly via Electron Cyclotron Resonance (ECR). As part of this study, the influence on the material and RF properties of Nb thin film of the deposition parameters like energy, coating temperature, interface with the substrate is investigated. The film surface and structure analyses are conducted with various techniques like X-ray diffraction, Transmission Electron Microscopy, Auger Electron Spectroscopy and RHEED. The microwave properties of the films are characterized on 50 mm disk samples with a 7.5 GHz surface impedance characterization system. This paper presents results on RF and cryogenic measurements in correlation with surface and material characterization for Nb films produced on insulating and metallic substrates. Emerging opportunities for developing multilayer SRF films with a new deposition system will also be highlighted.