Research on a 1.3 GHz annular electron beam powered multi-gigawatt microwave amplifier

We have been conducting experiments and computer simulations of annular electron beam powered microwave devices. This work includes the generation of an annular electron beam using the IMP puiser (500 kV, 5 Ω, 300 ns), the modulation of this beam by the Single Cavity Double Gap Modulator and a two cavity klystron-like amplifier, and the extraction or radiation of the microwave power via a Vlasov antenna. We have conducted experiments with two different geometries, one with the annular beam inside the microwave circuit and one with the microwave circuit inside the annular beam. We will present results of computer simulations from the 2-D code MAGIC and experiments for both geometries. We will also present results of simulations and experiments on injecting a magnetron signal into the two cavity klystron-like amplifier via RG-220 50 Ω cable. The MAGIC simulations of the amplifier are compared with the code Superfish to verify that the antenna model of MAGIC establishes the proper mode in the cavity.