Date of Award

12-2020

Degree Name

Master of Science

Department

Mechanical and Aerospace Engineering

First Advisor

Dr. Kristina Lemmer

Second Advisor

Dr. Nicholas Taylor

Third Advisor

Dr. Tianshu Liu

Keywords

Electrospray, electric propulsion, ionic liquid ion source, space propulsion, laboratory thruster

Access Setting

Masters Thesis-Open Access

Abstract

A single emitter ionic liquid ion source using porous borosilicate glass was developed. Two emitters with different radii of curvatures were tested using 1-ethyl-3-methylimidazolium tetrafluoroborate (EMI-BF4). I-V curves of the currents on the extractor electrode and a collector plate were obtained for potential differences between the emitter and the extractor ranging from 0 V to 3500 V. For the first emitter chip, extraction began near 2400 V. The highest emission current measured on the first chip was 80 µA at 3500 V with an interception current on the extractor of 4.86 µA. An new collector plate was used to obtain I-V traces of the second emitter chip for potential differences between the emitter and the extractor ranging from 0 V to 3300 V. The second emitter had a sharper tip and emission began between 2000 V and 2200 V on the emitter. The highest emission current of 50 µA using the second chip was at the peak applied voltage of 3300 V with a corresponding interception current of 0.71 µA. An electron suppression grid on the collector plate was tested to minimize the effect of secondary electron emission from the surroundings. Results show a substantial increase in collector current when a negative bias is applied to the grid implicating that electrons from secondary electron emission were successfully rejected.

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