A High-Power, Ceramic, RF Generator and Extractor

65357 Future linear colliders require efficient and cost effective high power radio frequency (rf) sources to accelerate electron/positrons. This project will develop a ceramic rf power extractor as a simple device to meet this need. In the ceramic rf power extractor, a train of high-charge electron bunches travels down the axis of a dielectric lined, circular metallic waveguide, radiating rf power into the ceramic tube. The radiated power is then extracted from the ceramic tube and coupled to an output waveguide for subsequent use. In Phase I, the properties of the rf power extractor were studied theoretically and numerically, and a ceramic power extractor capable of producing over 100 megawatts was designed. The ceramic material was specified, fabricated, and tested for dielectric properties and conformity to specifications. Fabrication and test plans for the ceramic rf power extractor were made. Phase II will design and build a high-power (500 MW), high-efficiency (>95%) ceramic rf power extractor, and test it at a high-power test stand in a national laboratory. As an intermediate goal, the 100 MW ceramic rf power extractor designed in Phase I will be built and tested for power handling and breakdown characteristics. Phase II also includes studies of higher order modes and beam breakup issues for the ceramic power extractor in a two beam acceleration scheme. Commercial Applications and Other Benefits as described by the awardee: The dielectric-based rf power source should substantially simplify the design and reduce the cost of high power rf transfer structures in future linear colliders. Beyond high energy physics and commercial accelerator applications, the ceramic rf power extractor could be used as a high-frequency, high-power signal generator capable of producing megawatts of power at high frequencies for such applications as long-range telecommunications at high-rate data transfer.