An improved version of a Marx bank circuit has been developed using 2N5551/2N5550 transistors as switching elements in avalanche mode which provides a negative pulse of about 4 kV amplitude and <or=ns rise time. The circuit has about 14 ns delay and <or=ns jitter.

https://iopscience.iop.org/article/10.1088/0957-0233/5/4/020/pdf

A transistorized Marx bank circuit providing sub-nanosecond high-voltage pulses

A fast cavity dumper for picosecond glass laser has been made. The optical and electrical characterization of the cavity dumper is described. An avalanche transistor Marx bank generator drives the cavity dumper. Up to 5 kV peak amplitude and 1.5 ns fall time negative polarity step pulses are generated by the Marx bank circuit. With a capacitive load like Pockels cell the pulse fall time increases to 4 ns. Optical switching times as fast as 2 ns (10%–90%) are experimentally measured. The contrast ratio of 1000 is obtained after a double pass through an amplifier. Single picosecond pulses are produced with an energy jitter of 10%.

A fast cavity dumper for a picosecond glass laser

The principle of operation of the transistor-based Marx bank circuit has been examined. It was experimentally observed that stage-wise increase of reverse voltage does not occur. This cannot be explained by the principle of operation understood so far. A new explanation, consistent with the experimental observations and associating current-mode second breakdown of transistors, is proposed. A few experimental observations made by earlier workers have also been justified in light of the new current-controlled mechanism.

The principle of operation of the avalanche transistor-based Marx bank circuit: A new perspective.

Streamer velocity is experimentally shown to vary with preionization in N2 and SF6. The velocity has been controlled over orders of magnitude by introducing pulsed preionization ahead of an already propagated streamer. The preionization is produced by pulsed uv irradiation. The pulsed electric field is uniform in the gap. Avalanche‐streamer conversion times were observed which agree well with prediction.

Preionization Control of Streamer Propagation

A fast (≤1 ns rise time) high‐voltage pulser circuit was developed using 2N5551/2N5550 transistors in avalanche mode as switching elements. This circuit has transistors in series stack configuration and provides ∼2 kV amplitude and ≤1 ns rise time into 50 Ω with a 13 ns delay and <500 ps jitter. A simple arrangement to generate two symmetrical opposite polarity pulses from single pulse of either polarity is also presented.

E.A. Jung

Papers

A solid state nanosecond pulser using Marx bank techniques