Design, fabrication and test of a 5 GHz klystron based on the kladistron principle

A new bunching method, named "kladistron" has been developed at CEA in order to provide high efficiency klystrons. A first "kladistron" prototype was designed and realized. It was adapted from the 4.9 GHz TH2166 from Thales, where the interaction line was transformed from 6 to 16 cavities. The design and fabrication phases of this prototype are developed in this paper. The kladistron prototype was tested in Thales facility. Its efficiency is finally lower (41 %) than expected (55 %), moreover it presents a spurious oscillation at 4.96 GHz. After analysis of the experimental results, it is concluded that the discrepancy between design and real frequencies is the cause for the low efficiency while the spurious oscillation results from a high gain peak at 4.96 GHz.