Flexible 50KV 18-Stage Solid-State Marx Modulator For Driving Capacitive Loads

Many cathode-driven beam injection systems require a low average power, highly stable and flexible modulator to generate an electron beam. The stability of the initial lower-power beam is vital to overall system efficiency. Stangenes Industries has developed a modulator system that is comprised of an 18-stage Marx modulator driving the primary of a pulse transformer within the confines of a 19" 5U rack with a 21" depth. The system operates with single-phase 115/230VAC input with <; 15A of input current. The modulator is a 75KW peak power 200W average load power 18-stage solid-state Marx modulator with pulse-to-pulse output variability of 3-50KV with <; 100V of output resolution. The pulse width is adjustable up to 5us and rep-rate is 500pps+ for driving loads up to 300pF with an isolated filament via a bifilar winding in the transformer. The system operates over the entire voltage range with a fixed charge voltage. The system controls are FPGA and MPU based and are Ethernet compatible with live diagnostic monitoring and control. Low-latency hardwired optical isolated and differential signaling receives off-system interlocks and an N-bit signal to choose between several operational states with preset output voltage, rep-rate and delay. These operation states can be adjusted inter-pulse at rep-rates up to 500pps. The trigger is also received via differential signaling with a propagation delay between signal reception and 10% pulse rise of <; 1us. The system incorporates a pulse transformer with a bifilar winding to provide 40W of DC filament power. All connections are made in the back of the unit with no water-cooling or insulating oil requirements.