Arc location predictor on a 2D composite surface in vacuum

Abstract

Conductors, insulators and semiconductors behave differently in the environment containing charged particles. For any sample substrate which consists either of these two or more has a specific charging property. In the charged environment, a differential potential is built up on metal and insulators kept adjacent to each other. If the surface potential exceeds the specified threshold voltage, a breakdown occurs on the substrate�s surface which results into release of heat and light energy. This is termed as an electrostatic discharge or an arc. Thus, discharges deteriorate the surface properties of the substrate and reduce its functional life. Hence, an understanding of such charging-arcing phenomenon on various substrate�s surface is essential. For this purpose, a dedicated facility for creating charged environment using electron gun and plasma source is developed and various parameters of discharge are measured and analyzed. As the size of the substrate is a major concern of performing experiments, an algorithm for predicting arc current waveform is developed simultaneously. This software is based on the basic details provided by the user. It is capable of generating a library of arc current waveforms on each arc favorable location. A dedicated database is obtained for each substrate having different geometrical shape. Generated arc waveform at any specified location is a function of its distance from substrate�s edges. It is based on 'arc image pixel manipulation technique'. Both experimental and simulated results are obtained for smaller sample substrates initially. Software generated waveform and actual waveform are quite comparable with each other. On successfully identifying arc location on the surface using the algorithm, use of CCD camera for the same can be avoided. A unique approach for reproducing a different waveform at each location by breaking the symmetry of the substrate is also discussed in the paper.