A 6kV Arbitrary Waveform Generator for the Tevatron Lens

TL;DR

This paper presents a novel 6 kV arbitrary waveform generator designed for the Tevatron Electron Lens, enabling precise bunch-by-bunch electron beam control to improve collider luminosity.

Contribution

It introduces a new inductive adder topology with five transformers for high-voltage, high-repetition-rate waveform generation in particle accelerators.

Findings

Achieved 143 kHz waveform output rate over 6 kV range

Designed a transformer-based inductive adder minimizing switching losses

Enabled complex, customizable waveforms for beam tune adjustments

Abstract

This paper reports on a 6 kV modulator built and installed at Fermilab to drive the electron gun anode for the Tevatron Electron Lens (TEL). The TEL was built with the intention of shifting the individual (anti)proton bunch tunes to even out the tune spread among all 36 bunches with the desire of improving Tevatron integrated luminosity. This modulator is essentially a 6 kV arbitrary waveform generator that enables the TEL to define the electron beam intensity on a bunch-by-bunch basis. A voltage waveform is constructed having a 7 {\mu}s duration that corresponds to the tune shift requirements of a 12-bunch (anti)proton beam pulse train. This waveform is played out for any one or all three bunch trains in the Tevatron. The programmed waveform voltages transition to different levels at time intervals corresponding to the 395 ns bunch spacing. Thus, complex voltage waveforms can be played out at a sustained rate of 143 kHz over the full 6 kV output range. This paper describes the novel design of the inductive adder topology employing five transformers. It describes the design aspects that minimize switching losses for this multi-kilovolt, high repetition rate and high duty factor application.