Electrical breakdown of nitrous oxide

Measurements of the spatial growth of prebreakdown ionisation currents and of the sparking potential VS 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, VS in any given circumstances being dependent not only on the product NdS (where dS 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.