An improved concept for a higher-order mode IOT

Summary form only given. Several years ago, the prototype of a higher-order mode inductive output tube (HOM-IOT), which was developed at CPI, suffered from various technological flaws, including warping of the large annular control grid structure. Means to prevent the warping of the grid have been found since then and the development of a 10 MW long-pulse, 1.3 GHz MBK (multibeam klystron) is being carried out at CPI for the TESLA project, sponsored by DESY, Hamburg, and this has led to an invention that permits the focusing of off-axis electron beams. This makes it possible to replace the quasi-annular beam in the HOM-IOT with an adequate number of electron beams which greatly increases the likelihood of the next super-power HOM-IOT being successful.