Field-Enhanced Superconductivity in High-Frequency Niobium Accelerating Cavities

Martinello, Martina; Checchin, Mattia; Romanenko, Alexander; Grassellino, Anna; Aderhold, Sebastian; Chandrasekeran, S. K.; Melnychuk, Oleksandr; Posen, S.; Sergatskov, Dmitri

doi:10.1103/physrevlett.121.224801

Cited by 34 publications

(32 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the insert, the power rise at 2 K is magnified in the medium field zone. As also noticed by experiments at FNAL [8], BCP treated 3.9 GHz cavities exhibited a natural anti-Q slope at medium fields. In this case, we noticed a 10% increase of the initial value around 15 MV=m, in line with the previously mentioned experimental results.…”

Section: B Vertical Acceptance Testing As Performed At the Lasa Facisupporting

confidence: 75%

Performance analysis of the European X-ray Free Electron Laser 3.9 GHz superconducting cavities

Bertucci

Bignami

Bosotti

et al. 2019

Phys. Rev. Accel. Beams

View full text Add to dashboard Cite

The limits of performance of the European XFEL 3.9 GHz superconducting cavities were investigated. Most cavities exhibited high field Q slope, reaching the breakdown field at approximately 22 MV=m. We hypothesize that this limit is a feature of high frequency cavities and can be explained by a thermal model incorporating field dependent surface resistance. The results obtained from simulations were in good agreement with experimental data obtained at 2 K.

show abstract

Section: B Vertical Acceptance Testing As Performed At the Lasa Facisupporting

confidence: 75%

Performance analysis of the European X-ray Free Electron Laser 3.9 GHz superconducting cavities

Bertucci

Bignami

Bosotti

et al. 2019

Phys. Rev. Accel. Beams

View full text Add to dashboard Cite

show abstract

“…In the framework of modern particle accelerators employing SRF cavities as accelerating devices, dissipation due to vortex motion under a microwave drive is a topic of central importance, inasmuch as trapped fields in the order of approximately 10 mG can increase the surface resistance of about 1 n [6], a large value for state-of-theart cavities capable of achieving surface-resistance values as low as 4 n at 2 K [29,30].…”

Section: Introductionmentioning

confidence: 99%

Vortex Dynamics and Dissipation under High-Amplitude Microwave Drive

Checchin

2020

Phys. Rev. Applied

Self Cite

View full text Add to dashboard Cite

In this paper, we describe the vortex dynamics under a high-amplitude microwave drive and its effect on the surface resistance of superconductors. The vortex surface resistance is calculated with a Monte Carlo approach, where the vortex equation of motion is solved for a collection of vortex flux lines, each oscillating within a random pinning landscape. This approach is capable of providing a detailed description of the microscopic vortex dynamics and in turn important insights into the microwave-field-amplitude dependence of the vortex surface resistance. The numerical simulations are compared against experimental data of vortex surface resistance at high microwave amplitude measured by means of bulk niobium superconducting radio-frequency cavities operating at 1.3 GHz. The good qualitative agreement of the simulations and experiments suggests that the nonlinear dependence of the trapped-flux surface resistance with the microwave field amplitude is generated by progressive microwave depinning and vortex jumps.

show abstract

“…The microwave reduction of R i (H) resulting from η(v) decreasing with v can contribute to the decrease of R s (H) with H observed on Nb resonators [105][106][107][108][109][110] . Other contributions to this effect could come from a nonlinear quasiparticle conductivity 111 which can be tuned by magnetic impurities and proximity-coupled oxide layer at the surface 98,112 .…”

Section: Discussionmentioning

confidence: 95%

Effect of random pinning on nonlinear dynamics and dissipation of a vortex driven by a strong microwave current

Pathirana,

Gurevich

2021

Preprint

View full text Add to dashboard Cite

We report numerical simulations of a trapped elastic vortex driven by a strong ac magnetic field H(t) = H sin ωt parallel to the surface of a superconducting film. The surface resistance and the power dissipated by an oscillating vortex perpendicular to the film surface were calculated as functions of H and ω for different spatial distributions, densities and strengths of pinning centers, including bulk pinning, surface pinning and cluster pinning. Our simulations were performed for both the Bardeen-Stephen viscous vortex drag and the Larkin-Ovchinnikov (LO) drag coefficient η(v) decreasing with the vortex velocity v. The local residual surface resistance Ri(H) calculated for different statistical realizations of the pinning potential exhibits strong mesoscopic fluctuations caused by local depinning jumps of a vortex segment as H increases, but the global surface resistance Ri(H) obtained by averaging Ri(H) over different pin configurations increases smoothly with the field amplitude at small H and levels off at higher fields. For strong pinning, the LO decrease of η(v) with v can result in a nonmonotonic field dependence of Ri(H) which decreases with H at higher fields, but cause a runaway instability of the vortex in a thick film for weak pinning. It is shown that overheating of a single moving vortex can produce the LO-like velocity dependence of η(v), but can mask the decrease of the surface resistance with H at a higher density of trapped vortices.

show abstract

Field-Enhanced Superconductivity in High-Frequency Niobium Accelerating Cavities

Cited by 34 publications

References 27 publications

Performance analysis of the European X-ray Free Electron Laser 3.9 GHz superconducting cavities

Performance analysis of the European X-ray Free Electron Laser 3.9 GHz superconducting cavities

Vortex Dynamics and Dissipation under High-Amplitude Microwave Drive

Effect of random pinning on nonlinear dynamics and dissipation of a vortex driven by a strong microwave current

Contact Info

Product

Resources

About