INVESTIGATION OF THERMOCURRENTS LIMITING THE PERFORMANCE OF SUPERCONDUCTING CAVITIES

As the surface resistance of superconducting cavities approach the theoretical limits parasitic effects limiting the performance came into focus of current research. One of these effects is that the quality factor of a cavity is impacted by the cool-down rate. We will present results from recent investigations on thermo-currents, driven by the temperature difference between the two material interfaces of the superconducting Niobium cavity and its Titanium helium-vessel. We will show that this leads to the presence of a magnetic field while the cavity transits into the superconducting state and impacts the quality factor of the cavity.