Can multilayer coatings raise the RF field above niobium's limit? · revision history

Revision 2

Accepted · core change · record

Changes against revision 1:

Title · changed
Revision 1: Can multilayer coatings raise the RF field above niobium's limit
Revision 2: Can multilayer coatings raise the RF field above niobium's limit?
Plain
A superconductor can carry an RF magnetic field only up to a maximum (the superheating field); thin layered coatings might push past niobium's value, but this has not been shown in a working cavity.
Precise · changed · core
Revision 1: The superheating field of clean Nb is $H_{\mathrm{sh}}$ approximately 2000-2400 G at low T, and the best Nb cavities reach $H_{\mathrm{pk}}$ near 2000 G. Determine whether superconductor-insulator-superconductor multilayers (Nb3Sn, NbN or similar layers thinner than the London penetration depth on Nb) raise the attainable RF field above bulk Nb $H_{\mathrm{sh}}$ in a cavity at $f \sim 1\, \mathrm{GHz}$, and give the maximal field versus layer thickness and defect density.
Revision 2: The superheating field of clean Nb is $H_{\mathrm{sh}}$ approximately 2000-2400 G at low T, and the best Nb cavities reach $H_{\mathrm{pk}}$ near 2000 G. Determine whether superconductor-insulator-superconductor multilayers ($\mathrm{Nb_3Sn}$, NbN or similar layers thinner than the London penetration depth on Nb) raise the attainable RF field above bulk Nb $H_{\mathrm{sh}}$ in a cavity at $f \sim 1\, \mathrm{GHz}$, and give the maximal field versus layer thickness and defect density.
Settled by
A coated cavity sustaining $H_{pk}$ above the bulk Nb superheating field at $T \sim 2\,\mathrm{K}$, with the field verified by calibrated RF measurement.
Kind
well-posed
Answer type
yes-no
References
(empty)
Literature status
open
Status note
(empty)
Posed since
2006

Decisions