Influences of gas pressure and applied voltage on electron beam generated by triggered pseudospark discharge

Abstract

Used widely in microwave devices and material processing, triggered pseudospark discharge can generate an electron beam, the adjustability of which is affected greatly by the working gas pressure and the applied voltage of the pseudospark discharge. This paper reports the development of an electron-beam source based on a single-gap triggered pseudospark discharge device. Its working performance, as measured by the peak beam current, charge quantity, and pulse width, was studied experimentally, and the results showed that the peak beam current increased initially and then decreased with increasing gas pressure. This was because the beam current was limited by the low plasma density at low pressures, while the electron scattering and ion neutralization during drift decreased the beam current at high pressures. The pulse width of the beam current was consistent with that of the loop current and was determined by the damping coefficient of the discharge circuit. With increasing gas pressure, the pulse width decreased gradually. When the gas pressure was constant, the peak beam current increased significantly with increasing applied voltage because of the enhanced electron-emission current and weakened electron scattering. The charge quantity of the beam current also increased with increasing applied voltage, but the pulse width decreased slightly. Based on the above results, this paper also reports qualitative analysis of the change of the discharge process corresponding to the variation of the electron-beam parameters with gas pressure and applied voltage.