Linear high-voltage ramp generator for use in selective field ionization of Rydberg atoms

Abstract

An electronic circuit has been constructed that generates a positive 3-kV linear ramp at adjustable slopes 125–500 V/μs, extendable to at least 1800 V/μs, for use in time-resolved selective field ionization of highly excited Rydberg atoms. Its principle of operation is as follows: An inductor, the primary of a 10:1 pulse transformer, is precharged with magnetic flux. The primary circuit is then opened and the collapse of flux is controlled by an integrator circuit with feedback from the secondary. An output circuit eliminates irregularities during the startup of the output pulse. The quiescent output is less than 40 mV. The output ramp, which can be fired at up to 1-kHz repetition rate and can drive typical capacitor-plate loads, has a slope that is constant within 2% from bottom to top, adjustable over a 4:1 range by a single potentiometer. The circuit has been extensively used for the detection and resolution of final-state ensembles in Rydberg spectroscopy and collision experiments.