Avalanche breakdown in n-hexane

Time lags to breakdown in n-hexane have been measured in high over-voltages, using approximately 100 ns width rectangular pulses. At a constant field, the time lags are divided into two types, N and B, at a 'critical distance' d. Above d c , Laue plots have almost similar kinked-line characteristics; below d c , a straight line is obtained. From the prebreakdown current estimated from the voltage waveforms, the ionisation coefficient, which increases with increasing applied fields, is estimated to be 6.4*10 3 cm -1 at 3.5 MV cm -1 , provided a single-electron avalanche is occurring.