Göttingen 2025 – wissenschaftliches Programm

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AKBP: Arbeitskreis Beschleunigerphysik

AKBP 4: AKBP Posters

AKBP 4.6: Poster

Dienstag, 1. April 2025, 16:30–18:00, ZHG Foyer 1. OG

New aspects of laser polishing of niobium for the production of superconducting cavity resonators — •Florian Brockner and Dirk Lützenkirchen-Hecht — Bergische Universität Wuppertal, Germany

Superconducting cavity resonators require niobium surfaces with low roughness, high chemical purity and isotropic properties. Laser polishing is a more environmentally friendly alternative to established chemical and electrochemical polishing processes and avoids the formation of impurities through non-contact processing.

The melting of the surface during polishing not only smoothes the surface but also heats it. This allows niobium to be doped during the polishing process. Both polishing and doping are strongly influenced by process parameters such as laser power, nitrogen pressure and material parameters related to the crystal structure of the material.

The process parameters were varied to investigate the influence on nitrogen deposition and roughness. The surface properties were analysed using optical profilometry and electron microscopy. The changes in chemical composition and nitrogen incorporation were studied by electron microscopy combined with energy dispersive X-ray spectroscopy and extended X-ray absorption fine structure. X-ray diffraction was also carried out.

Keywords: Laser polishing; Niobium cavities; Hydrofluoric acid free polish