A stacked transformer modulator that delivers high voltage at high rep-rate and duty factor

A modulator has been built to drive the gun anode of the Tevatron electron lenses (TEL) at Fermilab. High voltage applied to the gun defines electron beam current in order for the TEL to perform beam-beam compensation in the Tevatron on each of the 36 (anti)proton bunches. Every bunch requires its own defined current, and the value of current for each bunch is different with each Tevatron ¿store¿. These requirements demand the modulator deliver a complex output voltage waveform with a high duty factor and high repetition rate exceeding 5 kV. The modulator described here utilizes a novel circuit topology employing 5 pulse transformers whose secondaries are connected in series to produce complex voltage waveforms played out repeatedly having peak voltages of 6 kV with average periodic rates up to 423 kHz and short bursts at 2.5 MHz. This paper describes the design approach taken to leverage the virtues of transformers for high rep-rates and duty factors while dealing with the adverse effects of parasitics to achieve speed. Design details and performance results are presented.