Autoacceleration of electron beam and microwave radiation in the diaphragmed waveguide

One can increase considerably the energy of a portion of beam electrons by means of the autoacceleration mechanism. In our experiments, an electron accelerator with parameters 0.5–1.0 MeV, 20–30 kA, 40–50 ns was used. A hollow beam was passed through a diaphragmed waveguide. At its output, the electron spectrum and microwave spectrum were measured simultaneously. About 101 of the electrons increase their energy as compared with the maximum input energy, whereby 31 increase their energy more than by a factor of two. The energy multiplication for the tail electrons turns out to be 3–4 times the initial value. About 101 of the beam input power is spent on the increase of electron energy. The pulse microwave power generated is in the range 2.7–2.9 GHz and its total measured power was ∼ 0.4 GW, which corresponds to approximately 201 of the input beam power. Experiments show that effects of autoacceleration and microwave generation are interdependent and should be studied together.