München 2019 – wissenschaftliches Programm

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AKBP: Arbeitskreis Beschleunigerphysik

AKBP 15: Poster session

AKBP 15.18: Poster

Donnerstag, 21. März 2019, 16:30–18:00, Durchgangshalle

A review of Nb3Sn thin film processing for Nb SRF cavities — •Nils Schäfer, Márton Major, and Lambert Alff — Institute of Material Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany

Nowadays Nb is commonly used for superconducting radio frequency (SRF) cavities. Surface treatment can improve properties in the range of the penetration depth. Nb3Sn is a promising thin film material for SRF cavities as it can empower the cavity to operate at higher acceleration fields and higher temperatures. This is also achievable by a higher quality factor since the surface resistivity (RS) is lower with respect to Nb-only cavities at radiofrequency. Several approaches could be used for deposition of Nb3Sn thin film (e.g. sputtering, evaporation, and CVD; [Tan, TUPB055], [Pudasaini, TUPB067], [Pan, THPB057] and [Porter, WEXA03], Proc. SRF 2017). The applicability to successfully coat cavities was demonstrated for several processes with their respective disadvantages. Nb3Sn is either synthesized by a deposition of Sn on the Nb cavity or a stoichiometric deposition of Nb and Sn. Annealing forms the Nb3Sn thin film helps to further increase grain size and improve characteristics. Film Thickness, and especially stoichiometry are essential to make the most of the Nb3Sn material properties while under stoichiometric layers are still improve properties. A new modification to the sputtering process is made in the Advanced Thin Film Technology group to improve the stoichiometry of the layer. Work supported by the German Federal Ministry for Education and Research (BMBF) through grant 05H18RDRB2.