10th International Workshop on Thin Films and New Ideas for Pushing the Limits of RF Superconductivity

Successful Al2O3 coating of superconducting niobium cavities by thermal ALD

Sep 20, 2022, 2:20 PM

25m

CEBAF Center Auditorium

Beyond Nb: Alternate materials and mulilayer structures Beyond Nb: Alternate materials and mulilayer structures

Speaker

Getnet Kacha Deyu (Universität Hamburg | DESY (Remote))

Description

Al2O3 is one of the potential insulator materials in the superconductor-insulator-superconductor (SIS) multilayer coatings of superconducting radio-frequency (SRF) cavities for pushing their performance limits.
We report on the successful coating of two 1.3 GHz Tesla- shaped SRF cavities with 18 nm and 36 nm layers of Al2O3 deposited by thermal atomic layer deposition (ALD). The coating recipe was developed by thermal atomic layer deposition (ALD). The coating recipe was optimized with respect to different the applied process parameters such as exposure and purge times, substrate temperature and flow rates. After a proof-of-principle Al2O3 coating of a cavity, second the cavity maintained its maximum achievable accelerating field of more than 40 MV/m and no deterioration was observed. On the contrary, an improvement of the surface resistance above 10 MV/m has been observed, which is now further under investigation.

Presentation materials

Getnet Deyu_220920_Thin film workshop.pptx