HV PFN-Marx Development with 3D-Printed Spark Gaps for Extended Modulator System Operation

Multi-element Pulse Forming Networks (PFNs) in a stacked Marx configuration is a useful method for managing the fidelity of applied HV to dynamic loads. However, operational longevity of a Marx based system is limited by spark gap electrode erosion that requires maintenance periods that limit the usefulness of the modulator. The paper describes the development efforts of three (3) and five (5) capacitor/inductor element pulse forming networks to produce a 200 ns output pulse into an equivalent 100-Ω load with minimized trailing voltage reflection. The effort also included the design of a small, 50 kV rated, spark gap housing with rail gap electrodes mounted into 3D printed bodies for rapid and low-cost replacement necessary for extended modulator operation. Analysis of high-fidelity pulse shaping derived from experimental data are presented.