Magnetic flux compression generator powered electron beam experiments

We have combined several technologies in a rather conservative fashion to perform feasibility experiments to power a vacuum, electron beam diode with an explosive power supply. The magnetic flux compression generator used in these experiments was the 13.2-cm-wide by 52.8-cm-long plate generator. The output of this device was switched into an air-core, foil-wound, step-up transformer with a turn ratio of 30:1. The transformer and diode were connected through a 9-m-long piece of Sieverts high-voltage cable. The diode structure consisted of a high-voltage terminal on a stacked-ring grading structure with a 5-cm-diameter stalk to support a 12.7-cm-diameter field emission cathode. The cathode-anode gap was 2.5 cm, and the anode was 6.35-micron--thick aluminized mylar. Currents of greater than or equal to14 kA and voltages of greater than or equal to540 kV were achieved with a pulse length of greater than or equal to100 ns. Theoretical predictions agree with experimental performance until the diode shorted. However, this event limited the ultimate performance of the experiments. We consider diode shorting to be a major problem to be dealt with in future experiments involving >1 ..mu..s power pulses. This approach to powering electron beams should prove useful for experiments requiring only a few events ormore » for very high-energy diode design and scaling tests. 11 figs.« less