Paschen’s Law in Different Gases

Abstract

An experiment was performed to measure the Paschen curves of multiple gasses. Paschen curves are generated using Paschen’s equation. A plasma discharge tube was used to induce arcs of plasma in low pressure environments filled with each of the specific gasses. Using this apparatus, we measured the breakdown voltage Vb of each gas, as well as the pressure p of the environment, and the distance d between the two electrodes creating the plasma. The data collected was fit to Paschen’s equation in order to find the two unknown parameters A and B in the Paschen equation. Our fit method was tested against other experimental data to verify its effectiveness. The values gathered for A and B lead us to results that showed an incorrect value for the composition of atmospheric air. The results of our experiment indicated that there were too many problems with our apparatus to form any strong conclusions regarding the legitimacy of Paschen’s law, and our apparatus would likely need adjustments to make it usable, namely fixing leaks to maintain low pressures, and developing a way to keep the bulk of the tube filled with the specific gas rather than atmospheric air.