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AKBP: Arbeitskreis Beschleunigerphysik
AKBP 4: Radiofrequency and Beam Dynamics
AKBP 4.2: Talk
Wednesday, March 22, 2017, 09:45–10:00, MOL 213
Nitrogen doping of the niobium (100) single-crystal surface — •Guilherme Dalla Lana Semione1,2, Arti Dangwal Pandey1, Vedran Vonk1, and Andreas Stierle1,2 — 1Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22603 Hamburg, Germany — 2Fachbereich Physik Universität Hamburg, Jungiusstraße 9, 20355, Hamburg, Germany
Modern particle accelerators rely on niobium RF (Radio-Frequency) cavities for their operation and there is a big drive for performance improvement of such devices. Achieving a higher quality factor (Q0), will lead to higher luminosity while reducing the dynamic heat load, resulting in potential cost savings. Nitrogen doping is known to increase the performance of niobium cavities [1], however, the physical and chemical processes and phenomena involved are far from being understood [1,2]. In this work, niobium (100) single-crystals were subjected to a recently proposed nitrogen doping preparation, called "nitrogen infusion" [3]. The changes in the surface layers were monitored by in-situ X-Ray Reflectivity (XRR) measurements, and also investigated by ex-situ Grazing Incidence X-Ray Diffraction (GIXRD), X-Ray Photoemission Spectroscopy (XPS) and Scanning Electron Microscopy (SEM). The results show a decrease in the thickness of the native niobium oxide upon high-temperature annealing and the formation of an approximately 15nm thick niobium oxynitride layer during the nitrogen-infusion. [1] A. Grassellino et al, Supercond. Sci. Technol. 26 102001 (2013). [2] P. Dhakal et al, IEEE Tran. on App. Superc. 25 3500104 (2015). [3] Solyak N. et al, ECFA linear collider workshop (2016).