Electron beam behavior investigation in virtual cathode region

The paper experimentally studied the electron beam behavior in the virtual cathode formation region. A coaxial vacuum diode having a flat graphite cathode 30 mm in diameter served as the beam source. Electrons were injected into the cylindrical drift chamber through the wire anode. The accelerating voltage pulse amplitude was as high as /spl sim/270 kV, the beam current varied within 15-22 kA, its half-height duration being 20 ns. For the drift chamber used in experiments the injected beam was beyond the limit. Along with conventional diagnostics means a wire probe arranged in the anode plane transverse to the beam was used in this work for the current measurement. The probe recorded both the forward beam current and the current of electrons reflected from the virtual cathode. There are given the results of recording X-ray radiation from the virtual cathode formation region using a pinhole camera. It has been noted that the beam homogeneity produces a great effect upon the radiation generation efficiency.