Simple model for the rf field amplitude dependence of the trapped flux sensitivity in superconducting rf cavities

Sergio Calatroni; Ruggero Vaglio

doi:10.1103/PhysRevAccelBeams.22.022001

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Simple model for the rf field amplitude dependence of the trapped flux sensitivity in superconducting rf cavities

Sergio Calatroni, Ruggero Vaglio

DOI 10.1103/PhysRevAccelBeams.22.022001 · Physical Review Accelerators and Beams

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Abstract

The improvement of the performance of superconducting rf cavities has recently motivated a considerable research effort in order to elucidate the effect of trapped magnetic flux on the surface resistance Rs. In this paper, we show that, by introducing a nonlinear pinning force in the Gittleman-Rosenblum equations for the rf power dissipation due to a trapped magnetic flux in a superconductor, we can empirically describe the linear dependence on the rf field amplitude Brf0 of the additional surface resistance Rfl. We also show that the proportionality between the rf-field-dependent and -independent terms Rfl1 and Rfl0 and the frequency dependence of Rfl1 follow naturally from this approach.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Nb Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
Nb3Sn Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown