FIELD RECONSTRUCTION BY PASSBAND FREQUENCY MEASUREMENT AT THE ROSSENDORF SRF-GUN CAVITY

In this paper a method is presented that provides the field profile of a closed superconducting cavity only by measuring its passband frequencies with the applied RF coupling probes. This opens the possibility to estimate field deformations that are caused by the preload of the cavity tuner and its tuning during operation. The method was tested at the 3.5 cell Rossendorf SRF gun cavity [1] and a comparison between the measured and predicted field distribution demonstrates the accuracy within a range of 2%.