Influence of the RRR of Niobium on the RF Properties of Superconducting Cavities
The maximum accelerating field achievable in a superconducting niobium cavity is directly related to the thermal conductivity of the material, the Kapitza conductance between the niobium and the superfluid helium bath and the exponential behavior of the surface resistance with temperature. It is here highlighted that the RRR, an intrinsic physical measure which is related to the amount of impurities in the bulk, might affect these three parameters and hence the quench field. A new way of improving the niobium RRR by heat treatment is discussed as well as its impact on actual superconducting cavities.
KeywordsSurface Resistance Critical Magnetic Field High Temperature Heat Treatment Residual Resistivity Ratio Superconducting Cavity
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