Diagnostics for superconducting rf cavities

In the past a variety of diagnostic methods have been developed which allow to sense the ''overall'' behavior of superconducting rf cavities. Besides these methods temperature and X-ray mapping techniques as well as visual inspection give a more detailed insight into energy loss and electron phenomena of a superconducting cavity. With these techniques regions with increased rf - losses or electron emitting areas can be localized. It is hoped that these techniques together with surface diagnostic methods will give a better insight in the nature and causes of weak spots and will provide means for avoiding or eliminating such regions by adequate surface treatments. 15 refs