Kilohertz-range flash x-ray generator utilizing a triode in conjunction with an extremely hot cathode

Abstract

The construction and the fundamental studies of a kilohertz-range flash x-ray generator having a triode in conjunction with an extremely hot cathode are described. This generator consisted of the following components: a constant-high voltage power supply, an energy storage condenser of 100 nF, a constant high-voltage power supply for regulating an initial grid voltage of −1.6 kV, a grid pulser, and an x-ray tube. The x-ray tube was of an enclosed-triode type and consisted of the following major parts: an anode rod made of copper, a plane anode tip (target) made of tungsten, a focusing electrode made of iron, a hot cathode (filament) made of tungsten, a grid made from tungsten wire, and a glass tube body. The energy storage condenser was charged from 50 to 70 kV, and the electric charges in the condenser were discharged repetitively to the x-ray tube by the grid electrode driven by the grid pulser. The temperature of the filament was about 2000 K, and the cathode current was primarily controlled by the grid voltage and its value was less than 1.2 A. The pulse widths were about 1 μs and the maximum repetitive frequency was about 2.0 kHz. The x-ray intensity was 19.7 nC/kg at 0.5 m per pulse with a peak grid voltage of 1.0 kV and a condenser charged voltage of 70 kV.