Speaker
Description
Niobium coated copper accelerating cavities have demonstrated their strong potential in accelerators such as LEP, LHC and HIE-ISOLDE and could become a technology of choice for such a machine as the FCC.
On the way of further improving thin-film coated copper cavities performances one proposes to substitute niobium by a superconductor that could lead to a higher quality factor as well as a higher operational accelerating gradient. The intermetallic compound Nb3Sn due to its very low Bardeen-Cooper-Schrieffer (BCS) surface resistance and high superheating field is considered as an ideal candidate. The 18.3 K critical temperature of Nb3Sn could also facilitate cavity operation at 4.2 K and thereby reduce cryogenic cooling costs.
This research aims to study the properties of Nb3Sn thin films deposited on copper samples using direct current magnetron sputtering system with a stoichiometric target Nb:Sn (ratio 3:1). The dependence of the morphology, microstructural and superconducting properties of the films on the deposition and annealing parameters has been investigated, along with the influence of the copper substrate. The potential of the coating method has been validated by the production of high-quality Nb3Sn films on copper with critical temperatures up to Tc ~ 17.4 K.
