Time-resolved thermometry for superconducting deflecting cavity development

A time-resolved thermometry system has been developed for the superconducting deflecting cavity development at Argonne National Lab. The time resolution of the thermometry can be as fast as 50 μs. The spatial distribution as well as the temporal evolution of the temperature rises can be recorded. Using this system, we demonstrate that the common loss mechanisms in a superconducting rf cavity have different temporal evolution characteristics. Thus we can make use of these characteristics to locate and identify different losses with better accuracy. Two of the four fabricated deflecting cavities have been investigated, and the thermometry system has successfully located and identified the cavity limitations. Based on the thermometry findings, proper treatments have successfully improved the cavity performance.