Ultra-high quality factors in superconducting niobium cavities in ambient magnetic fields up to 190 mG
Ultra-high quality factors in superconducting niobium cavities in ambient magnetic fields up to 190 mG
Ambient magnetic field, if trapped in the penetration depth, leads to the residual resistance and therefore sets the limit for the achievable quality factors in superconducting niobium resonators for particle accelerators. Here, we show that a complete expulsion of the magnetic flux can be performed and leads to: (1) record …