Mechanism Analysis of the Flashover Quenching the Photoconductive Semiconductor Switch in $\hbox {SF}_{6}$

The authors designed the voltage withstand test of the photoconductive semiconductor switch (PCSS) in which the electrode gap was 18 mm in the condition of the pulsed laser triggered. During the experiments, the flashover quenching the photon-activated charge domain (PACD) has been observed, namely, when the flashover occurred, the pulse current amplitude of semi-insulating GaAs PCSS was lower than the normal value without flashover and the rise time of the output current increased. The experiment indicates that the current output characteristics of PCSS contain the information of the flashover, when the flashover occurs with the discharge of the PCSS. The analysis denotes that the secondary electron emission in the flashover quenches the PACD and ultimately quenches the PCSS. The external electric field of the PACD modulated by the secondary electron emission determines if the PACD is to be quenched or not. The Gunn domain is imported to describe the critical state where the flashover quenches the PACD and the threshold condition has been given.