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Description
Nb3Sn thin film cavities are new generation of superconducting cavities, which have the potential to replace traditional pure niobium cavities owing to their superior theoretical radio frequency (RF) performance. Higher theoretical acceleration gradient and quality factor give Nb3Sn cavities more possibilities in the future. There have been relatively high success in producing such cavities by Sn diffusion method. The production of such cavities through thin film deposition on copper cavity foresees lower cost of material and at the same time profiting from higher thermal conductance of copper .
At Daresbury Laboratory, we have commissioned a new Nb3Sn deposition facility for depositing a Nb cavity with Nb3Sn. The system is based on planar magnetron where the optimised parameters for Nb3Sn on flat surfaces is stablished inside the segmented Nb cavity.
The Cavity was deposited at 650 °C using two special designed 2 inch magnetrons travelling inside cavity simultaneously from each end of the cavity. The deposition was done at optimum deposition parameter in DC power.
We further report on the RF performance of the cavity at 4 K in liquid He, demonstrating quality factor Q0 of 3x1010 comparable to Nb cavity at 2 K and extending to accelerating gradient of up to 16 MV/m.