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The fundamental studies of the repetitive type of flash x-ray generator utilizing
an enclosed-type diode with a ring-shaped graphite cathode for soft radiography are
described. This generator consisted of the following essential components: a
constant high-voltage power supply, an energy storage condenser of lOOnF, a highvoltage
pulser, a repetitive impulse switching system, and a flash x-ray tube. The
pulser employed a modified two-stage Marx circuit with a capacity during main
discharge of 425pF. The x-ray tube was of the enclosed-diode type and consisted of
the following major devices: a rod-shaped anode tip made of tungsten, a ring
cathode made of graphite, an x-ray window made of beryllium, a spattering shield
made of stainless steel, and a tube body made of glass. Two condensers in the
pulser were charged from 50 to 70kV, and the output voltage was about 1. 6 times the
charged voltage. Both the peak tube voltage and the peak tube current increased
according to increases in the charged voltage, and the maximum values of the
voltage and the current were about 90kV and 0. 5kA, respectively. The pulse width
was about lOOns, and the x-ray intensity was less than 2. OpC/kg at 0. 5m per pulse.
The repetition frequency was less than 50Hz, and the maximum size of the effective
focal spot was nearly equivalent to the anode diameter of 3. 0mm.
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