High-voltage pulse generator for time-of-flight mass spectrometry in electrospray thrusters

Electrospray thrusters exhibit diverse operational modes based on the nature of ejected particles. Time-of-flight mass spectrometry is frequently employed to analyze the composition of the plume. This study introduces a novel converter-based bipolar high-voltage pulse generator aimed at producing synchronized bipolar high-voltage pulses with controllable voltage levels and frequencies, specifically tailored for the study of electrospray thrusters. The proposed topology generates bipolar high-voltage rails from a low-voltage power source through the forward-flyback with Cockcroft-Walton voltage multiplier topology. Subsequently, fast high-voltage MOSFETs are employed to generate high-voltage pulses. This paper outlines the operational principles and design methodologies of the pulse generator. Experimental verification corroborates its operational principles and functionalities, revealing that the pulse rise and fall times consistently remain below 30 ns, while the voltage can be tuned within the range of 300-1000 V. An electrospray thruster was employed to conduct a thorough and practical validation of the high-voltage pulse generator. This included generating time-of-flight curves and mass spectra of the plume, resulting in precise differentiation of all particles present.