N-doped surfaces of superconducting niobium cavities as a disordered composite

Wolfgang Weingarten

doi:10.1109/TASC.2018.2836946

N-doped surfaces of superconducting niobium cavities as a disordered composite

Accelerator Physics 2018-08-01 v5

Authors: Wolfgang Weingarten

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Abstract

The Q-factor of superconducting accelerating cavities can be substantially improved by a special heat treatment under N2 atmosphere (N-doping). Recent experiments at Fermi National Laboratory investigated the dependence of Q on the RF frequency and showed, unexpectedly, both an increase and a decrease with the RF field amplitude. This paper shall explain this finding by extending a previously proposed model founded on the two fluid model of RF losses, percolation and the proximity effect in a disordered composite.

Keywords

superconducting niobium cavities N-doping Q-factor disordered composite RF losses proximity effect

Cite

@article{arxiv.1708.02841,
  title  = {N-doped surfaces of superconducting niobium cavities as a disordered composite},
  author = {Wolfgang Weingarten},
  journal= {arXiv preprint arXiv:1708.02841},
  year   = {2018}
}

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