Modulator-repetitively pulsed field emission electron beam gun interface

A field emission electron beam gun is repetitively pulsed with a modulator in a Blumlein arrangement. The modulator is operated in an unmatched condition with the output connected directly to the gun. The gun is a time-varying monotonically decreasing impedance load while the modulator impedance is constant. The modulator-gun configuration produces an initial voltage peak which approaches twice the value of the charge voltage to promote gun emission. After the initial peak the load voltage plateaus at a value determined by the gun impedance. Peak voltages in excess of 350 kV and peak currents up to 8 kA have been delivered in 5 microsec pulses by the modulator to the gun. The modulator routinely operates at 50 Hz repetition rate, 135 kV recharge voltage and about 3 amps of average current.