Electrical breakdown of nitrous oxide

Abstract

Measurements of the spatial growth of prebreakdown ionisation currents and of the sparking potential V_S have been performed for N₂O within the range 145 × 10⁻¹⁷ < E/N < 175 × 10⁻¹⁷ V cm², where E is the electric field and N the gas number density, which was in the range 1.6 × 10¹⁸−20 × 10¹⁸ cm⁻³. The results show that the breakdown strength is about half that of SF₆, V_S in any given circumstances being dependent not only on the product Nd_S (where d_S is the sparking distance) but also on N. Analysis of the measurements of prebreakdown ionisation currents shows that the explanation of this behaviour lies primarily in the fact that the effective primary-ionisation coefficient is not linearly dependent on N, probably because of the occurrence of collisional detachment from NO^- which is formed in one of the many ion-molecolue reactions known to occur in N₂O.