A 500 kV, 10 kA, 40 ns coaxial Marx generator pulser for cable fed flash x-ray system

Abstract

Flash x-ray (FXR) systems are used for dynamic radiography. Depending on the speed of the object, these systems typically require a very short pulse duration (∼25 ns) for image acquisition without motion blur. The conventional Marx generators with zigzag discharge paths result in higher inductance; hence, they do not meet the requirement of shorter pulse duration (30–40 ns) and low impedance (40–60 Ω) simultaneously. A coaxial Marx generator has been designed and developed, which is capable of generating 500 kV peak voltages and 10 kA peak current within a 40 ns pulse duration. The CST simulation of the coaxial Marx generator has been carried out to validate the design parameters. The FXR electron beam diode is powered by this Marx generator. Experiments were carried out to measure the x-ray parameters like pulse width, source size, x-ray energy spectrum, penetration depth, and cone angle. The maximum measured x-ray dose was 62 mR at 1 m distance from the source window. The x-ray radiograph demonstrates a penetration depth of 32 mm in steel kept at 2.5 m distance from the source for 500 kV diode voltages.