# Field dependent surface resistance of niobium on copper cavities

@article{Junginger2014FieldDS,
title={Field dependent surface resistance of niobium on copper cavities},
author={Tobias Junginger},
journal={Physical Review Special Topics-accelerators and Beams},
year={2014},
volume={18},
pages={072001}
}
• T. Junginger
• Published 2 December 2014
• Materials Science, Physics
• Physical Review Special Topics-accelerators and Beams
The surface resistance ${R}_{\mathrm{S}}$ of superconducting cavities prepared by sputter coating a niobium film on a copper substrate increases significantly stronger with the applied rf field compared to cavities of bulk material. A possible cause is that the thermal boundary resistance between the copper substrate and the niobium film induces heating of the inner cavity wall, resulting in a higher ${R}_{\mathrm{S}}$. Introducing helium gas in the cavity, and measuring its pressure as a…

## Figures and Tables from this paper

Superconducting thin films are a possible alternative to bulk niobium for superconducting radio frequency cavity applications. Thin film cavities have produced larger Q0 than bulk niobium at low
• Physics
Physical Review Accelerators and Beams
• 2019
Superconducting niobium film cavities deposited on copper substrates (Nb/Cu) have suffered from strong field-dependent surface resistance, often referred to as the Q-slope problem, since their
• Physics
Physical Review Accelerators and Beams
• 2022
We propose a model to explain power dissipation leading to the formation of hot spots in the inner walls of niobium thin film superconducting RF cavities. The physical mechanism that we explore is
• Physics
Superconductor Science and Technology
• 2022
We present a study of radio frequency properties of niobium films deposited on copper by two different approaches based on High Power Impulse Magnetron Sputtering, namely with a DC voltage biased
• Physics
• 2017
We present the results of rf measurements on a niobium–copper clad superconducting radio-frequency cavity with different cooldown conditions and residual magnetic field in a vertical test Dewar in
• Physics
• 2017
Point contact tunneling and low energy muon spin rotation are used to probe, on the same samples, the surface superconducting properties of micrometer thick niobium films deposited onto copper
• Physics
• 2015
Muon spin rotation ( μ SR) and point contact tunneling (PCT) are used since several years for bulk niobium studies. Here we present studies on niobium thin ﬁlm samples of diﬀerent deposition
• Physics
Physical Review Accelerators and Beams
• 2018
We present a general method to derive the magnetic field dependence of the surface resistance of superconductors from the Q-curves obtained during the cryogenic tests of cavities. The results are
• Physics
• 2016
Cornell has developed a TE mode sample host microwave cavity in order to study large, flat samples of novel SRF materials. In recent calibration tests, the cavity was shown to reach peak magnetic
CRABBING SYSTEM FOR AN ELECTRON-ION COLLIDER Old Dominion University, 2017 Director: Dr. Jean Roger Delayen Co-Director: Dr. Mauro Napsuciale Mend́ıvil As high energy and nuclear physicists continue

## References

SHOWING 1-10 OF 15 REFERENCES

Radio-frequency superconducting (SRF) cavities are widely used to accelerate a charged particle beam in particle accelerators. The performance of SRF cavities made of bulk niobium has significantly
• Physics
• 2003
A 400-MHz niobium quadrupole resonator has been manufactured to study the rf properties of superconducting bulk and thin film samples at low temperatures. We describe the apparatus, i.e., the
• Physics
• 2014
We report a strong effect of the cooling dynamics through Tc on the amount of trapped external magnetic flux in superconducting niobium cavities. The effect is similar for fine grain and single
• Physics
Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences
• 1953
The penetration depth, λ, in superconducting tin at 0° K has been found to be capable of variation by the addition of impurity, 3% of indium causing it to be nearly doubled, although the
• Physics
• 1991
The contribution of the Mattis-Bardeen theory to the understanding of the surface impedance of superconductors and normal conductors is reviewed. The early theoretical and experimental studies of the
• Physics
• 2000
The conceptional design of the proposed linear electron-positron collider TESLA is based on 9-cell 1.3 GHz superconducting niobium cavities with an accelerating gradient of Eacc >= 25 MV/m at a
• Physics
Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences
• 1964
The thermal expansion of copper has been determined at temperatures down to 2 °K by means of an electrical capacitance technique. By measuring three-terminal capacitances in a ratio-transformer