Nb3Sn coating of SRF cavity by co-sputtering from a composite target

Journal Article · Mon Aug 04 04:00:00 EDT 2025 · No journal information

OSTI ID:2998982

Shakel, Md Sharifuzzaman ^[1]; Eremeev, Grigory V. ^[2]; Valente-Feliciano, Anne-Marie ^[3]; Pudasaini, Uttar ^[3]; Hani E. Elsayed-Ali, Hani Elsayed-Ali ^[4]

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1. Old Dominion U.; Jefferson Lab
2. Fermilab
3. Jefferson Lab
4. Old Dominion U.

We deposited Nb3Sn film on the inner surface of a 2.6 GHz Nb superconducting radiofrequency (SRF) cavity by co-sputtering using a composite of Nb and Sn tube targets in a DC cylindrical magnetron sputtering system, followed by thermal annealing of the coated cavity. An aluminum mockup cavity, replicating a 2.6 GHz Nb SRF cavity geometry, was utilized to optimize the deposition parameters, resulting in co-sputtered Nb-Sn films with Sn content of 32 - 42 at. % on the beam tubes and equator positions. Several annealing conditions were investigated to improve the surface homogeneity of the Nb3Sn film. The best co-sputtered Nb-Sn film was achieved after annealing at 600 C for 6 h, followed by annealing at 950 C for 1 h. The best process was applied to a Nb cavity, which was RF tested in cryogenic dewar. RF testing of the Nb3Sn-coated cavity demonstrated the superconducting transition temperature (Tc) close to the highest reported, achieving a Tc of 17.78 K. The Nb3Sn cavity underwent a light Sn recoating process, followed by additional RF testing, resulting in enhancement of the RF performance of the cavity, primarily due to the improved surface homogeneity of the Nb3Sn coating.

• Research Organization: Old Dominion U.; Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
• Sponsoring Organization: US Department of Energy
• DOE Contract Number: 89243024CSC000002
• OSTI ID: 2998982
• Report Number(s): FERMILAB-PUB-25-0591-TD; JLAB-ACC-25-4329; oai:inspirehep.net:2957791; arXiv:2508.02894
• Journal Information: No journal information, Journal Name: No journal information
• Country of Publication: United States
• Language: English