Electron angular distribution in an opening-switch-driven coaxial diode

Summary form only given. Characterization of the angular distribution of electrons produced in a coaxial high-current relativistic electron beam diode may be important in evaluating the applications of these diodes. This angular distribution has not previously been measured for an opening-switch-driven low impedance coaxial diode. Because the opening switch may have plasma in the vicinity of the diode, it is expected that the angular distribution may differ from that found in a closing-switch driven system. On the DECADE Module I, the distribution was measured using a multiple-aperture shadowbox imaging system, using radiochromic film to record the distribution. Nominal DM1 electron beam parameters are 1.7 MV peak voltage, 700 kA peak current, and 40 ns FWHM produced with a 6 inch diameter cathode. Twenty-one 0.332 cm diameter apertures on a grid pattern with a center-to-center spacing of 4.45 cm are distributed over the the central 8 inch diameter of the anode.