Shakel, M.S. Elsayed-Ali, H. Eremeev, G.V. Pudasaini, U. Valente-Feliciano, A-M. JACoW Publishing Geneva, Switzerland 2673-5504 978-3-95450-234-9 10.18429/JACoW-SRF2023-TUPTB019 English 429-432 cavity SRF site vacuum MMI Contribution to a conference proceedings 2023 2023-09 https://doi.org/10.18429/JACoW-SRF2023-TUPTB019 https://jacow.org/srf2023/papers/tuptb019.pdf A DC cylindrical magnetron sputtering system has been commissioned and operated to deposit Nb₃Sn onto 2.6 GHz Nb SRF cavities. After optimizing the deposition conditions in a mock-up cavity, Nb-Sn films are deposited first on flat samples by multilayer sequential sputtering of Nb and Sn, and later annealed at 950 °C for 3 hours. X-ray diffraction of the films showed multiple peaks for the Nb₃Sn phase and Nb (substrate). No peaks from any Nb-Sn compound other than Nb₃Sn were detected. Later three 2.6 GHz Nb SRF cavities are coated with ~1 µm thick Nb₃Sn. The first Nb₃Sn coated cavity reached close to E_{acc} = 8 MV/m, demonstrating a quality factor Q₀ of 3.2 × 10⁸ at Tbath = 4.4 K and E_{acc} = 5 MV/m, about a factor of three higher than that of Nb at this temperature. Q₀ was close to 1.1 × 10⁹, dominated by the residual resistance, at 2 K and E_{acc} = 5 MV/m. The Nb₃Sn coated cavities demonstrated Tc in the range of 17.9 ¿ 18 K. Here we present the commissioning experience, system optimization, and the first results from the Nb₃Sn fabrication on flat samples and SRF cavities.