Recent Investigations of the Orsay Group on RF Properties and Applications of Superconducting Cavities

After a large development of our experimental studies on high stability oscillators, a theoretical work on different physical processes able to induce localized transitions to the normal state at high field level in superconducting cavities, is in progress. A theoretical study of beam dynamics in low energy electron linacs (in the 1-5 MeV range) shows that a standing wave structure have interesting focusing properties for short bunches injected in the "unstable" rhase domain, and that a single TM010 cavity could be used to obtain electrons of 2 MeV.