Dc Gas Breakdown and Townsend Discharge in Co2

Abstract

We report the breakdown curves and current-voltage characteristics (CVC) of the Townsend mode DC discharge we have measured in carbon dioxide. We compare the breakdown curves measured with two different techniques. With the first technique we regard as breakdown voltage the maximum voltage which we can apply across the electrodes without igniting the discharge with fixed values of the inter-electrode distance and the gas pressure. With the second technique we register the CVC of the Townsend mode in the μA-mA range and then extrapolate them to zero current. We reveal that in the nA-μA range the CVCs of the Townsend mode may have a complicated behavior due to the formation of the space charge. Therefore the second technique furnishes incorrect values of the breakdown voltage.