Electrical Breakdown Studies of Partial Pressure Argon Under KHz Range Pulse Voltages

Abstract

Electronics operating in a partial vacuum may experience a gaseous breakdown when strong electric fields are present. The breakdown voltage for a gas decreases as the pressure decreases from atmospheric conditions and reaches a minimum. After this minimum breakdown voltage, it starts to increase as pressure further decreases for a given fixed electrode spacing. This idea was first expressed in the early 1900’s by Paschen Law. An increase in operating frequency can also cause a breakdown to occur at lower applied voltage levels. In this work, the breakdown characteristics for Argon are studied in partial vacuum from 0.1 Torr to 3 Torr. First, a dc analysis is performed for electrodes with point-plane and point-point geometries. A pressure sweep analysis is then performed for the same electrode geometries with a unipolar pulsed signal for fixed frequency in the range of 20-200 kHz with a fixed duty cycle of 50%. A frequency sweep is then performed for a range of fixed pressures from 0.1 Torr to 3 Torr. Lastly, a duty cycle sweep is performed from 10% to 90% for the same range of fixed pressures and frequencies. Data is captured during each gaseous breakdown event for analysis. The breakdown voltage characteristics are discussed as a function of the applied signal and environmental pressure.