HIGHLY-EFFICIENT 20-MW L-BAND MULTI-BEAM KLYSTRON
The overall goal of this project was to develop and demonstrate a novel two-stage multi-beam klystron (TS-MBK) for use in accelerator, medical, national security, medical, and environmental cleanup applications. The novelties embodied in the TS-MBK design include use of hollow beams to obtain strong coupling to cavities, and post acceleration after bunching to reduce the beam’s energy spread to allow an exceptional electronic efficiency that we predict can reach 90%. During Phase I of this project, Omega-P R&D refined its conceptual design of the 1.0 GHz TS-MBK, and collector design and cooling requirements for several levels of average power output. If, as was the case, it turned out that estimated costs for fabrication and testing of a full 12-beam TS-MBK prototype would exceed available Phase II funding, our Plan-B would have be adopted. In it, a single-beam version would have been designed and built, with all specifications identical to the 12-beam version, except that the average power level would be reduced by a factor of about 12. This one-beam version would still allow evaluation of the efficacy of our design concept for implementing two stages, including prevention of radiation loss at the HV gap, and for demonstrating the predicted 90% electronic efficiency and the absence of reflected electrons from the collector reaching the cathodes. But the absence of the expected industrial partner in further development of this novel RF source made it impractical for advancing the project into Phase II.