Co-sputter deposition of Nb₃Sn layer into SRF cavity using Nb-Sn composite target

Conference · Wed Jan 28 00:00:00 EST 2026 · JACoW

DOI:https://doi.org/10.18429/JACoW-NAPAC2025-WEP015· OSTI ID:3026719

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

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

Nb₃Sn, with its superior superconducting critical temperature (Tc ~18.3 K) and superheating field (Hsh ~400 mT), is considered a promising material for superconducting radiofrequency (SRF) cavities, offering enhanced cryogenic performance compared to bulk niobium cavities. A Nb₃Sn coating technique has been developed for Nb SRF cavities using co-sputtering of Nb-Sn composite target in a DC cylindrical magnetron sputtering system. The composite target configuration and discharge conditions for co-sputtering were optimized to deposit Nb-Sn films on flat Nb substrates, followed by annealing to form Nb₃Sn. Multiple strategies have been explored to improve the surface homogeneity of the Nb₃Sn coating, including optimizing a two-step annealing process, annealing in Sn vapor, and a light Sn recoating process. A 1.5 µm Nb-Sn co-sputtered film was deposited on the interior of a 2.6 GHz Nb SRF cavity and annealed at 600 °C for 6 h, followed by 950 °C for 1 h. Cryogenic RF testing of the annealed cavity demonstrated a Tc of 17.8 K, confirming the formation of Nb₃Sn. Then, the annealed cavity underwent a light recoating treatment and attained a quality factor (Q0) of 8.5E+08 at 2.0 K.

• Research Organization: Old Dominion U.; Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
• Sponsoring Organization: US Department of Energy
• DOE Contract Number: 89243024CSC000002
• OSTI ID: 3026719
• Report Number(s): FERMILAB-CONF-25-0321-TD; oai:inspirehep.net:3119589
• Resource Type: Conference paper
• Conference Information: Journal Name: JACoW
• Country of Publication: United States
• Language: English