Effect of interstitial impurities on the field dependent microwave surface resistance of niobium

Abstract

Previous work has demonstrated that the radio frequency surface resistance of niobium resonators is dramatically reduced when nitrogen impurities are dissolved as interstitial in the material. The origin of this effect is attributed to the lowering of the Mattis and Bardeen surface resistance contribution with increasing accelerating field. Meanwhile, an enhancement of the sensitivity to trapped magnetic field is typically observed for such cavities. In this paper we conduct the first systematic study on these different components contributing to the total surface resistance as a function of different levels of dissolved nitrogen, in comparison with standard surface treatments for niobium resonators. Adding these results together we are able to show for the first time which is the optimum surface treatment that maximizes the Q-factor of superconducting niobium resonators as a function of expected trapped magnetic field in the cavity walls. These results also provide new insights on the physics behind the change in the field dependence of the Mattis and Bardeen surface resistance, and of the trapped magnetic vortex induced losses in superconducting niobium resonators.

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Cited by in corpus (21)

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• Ultra-Low Surface Resistance via Vacuum Heat Treatment of Superconducting Radiofrequency Cavities
• Time-dependent Ginzburg-Landau treatment of RF Magnetic Vortices in Superconductors: Vortex-Semiloops in a Spatially Nonuniform Magnetic Field
• Flux expulsion in niobium superconducting radio-frequency cavities of different purity and essential contributions to the flux sensitivity
• On the quest of low temperature nitrogen infusion relevant for superconducting Nb based radio-frequency cavities
• Axion production and detection with superconducting RF cavities
• The Role of Magnetic Flux Expulsion to Reach Q0>3x10^10 in SRF Cryomodules
• Revealing the role of nitrogen on hydride nucleation and stability in pure niobium using first principles calculations
• Frequency dependence of trapped flux sensitivity in SRF cavities
• Q-factor optimization for high-beta 650 MHz cavities for PIP-II
• Depth-resolved measurements of the Meissner screening profile in surface-treated Nb
• High-Field Q-slope Mitigation due to Impurity Profile in Superconducting Radio-Frequency Cavities
• Surface impedance measurements on Nb${}_3$Sn at high magnetic fields
• Field emission mitigation studies in LCLS-II cavities via in situ plasma processing
• Determination of the magnetic field dependence of the surface resistance of superconductors from cavity tests
• Vortex Dynamics and Dissipation Under High-amplitude Microwave Drive
• Simple model for the RF field amplitude dependence of the trapped flux sensitivity in superconducting RF cavities
• Signatures of Enhanced Superconducting Properties in Niobium Cavities
• Fluxon-induced losses in niobium thin-film cavities revisited
• Quantifying Trapped Magnetic Vortex Losses in Niobium Resonators at mK Temperatures
• Improved high-gradient performance for medium-velocity superconducting half-wave resonators: Surface preparation and trapped flux mitigation