Measurement of Ionization and Attachment Coefficients in Carbon Monoxide in Uniform Fields

Measurements of pre-breakdown currents in uniform field conditions, in carbon monoxide at different pressures, in the E/p range of 36 to 200 v cm-1 (mm Hg)-1 indicate the presence of electron attachment. It is suggested that the mechanism of negative ion formation is due to dissociative attachment, therefore values of α and the dimensionally equivalent attachment coefficient η have been computed from the semi-logarithmic plots of current against electrode separation, by employing the modified Townsend equation for the growth of current. Static breakdown potentials have been measured up to pd~ 1050 mm Hg cm (where p is the pressure and d the gap length) and show that Paschen's law is obeyed. Further, the values of secondary coefficient γ have been computed from upcurving of the semi-logarithmic plots of current against electrode separation. The values of breakdown potential calculated from the breakdown criterion are in good agreement with the measured values, showing that the static breakdown in carbon monoxide is brought about by the Townsend build-up mechanism.