A 250 kW Multiple Beam Higher Order Mode Inductive Output Tube

We propose to use a Multiple Beam IOT approach. This configuration has several small cathodes arranged in a circular pattern. This provides a thermally and mechanically robust arrangement for supporting the modulating grids and forming the input cavity of the device. Each individual beam, or beamlet, will traverse the IOT circuit in its own individual beam tunnel. This will eliminate the possibility of coupling RF power from the output circuit toward the electron gun since the individual beam tunnels will not support the coaxial transmission line mode. This configuration will facilitate development of RF sources in the range of interest: 200 MHz to at least 1 GHz. The proposed program will investigate each of the critical issues involved in development of the 250 kW, L-Band multiple beam IOT and determine if solutions can be developed to justify construction and testing of a prototype in a Phase II program.