Boundary area between gas and vacuum breakdown mechanism

This paper considers the transition from the gas breakdown mechanism to the vacuum breakdown mechanism. Gas breakdown mechanisms at the points of Paschen minimum and on the left from it, as well as vacuum breakdown mechanisms and their dependence on experimental parameters have been analysed. In accordance with this analysis, an experiment with the following variable parameters has been conceived and carried out: type of gas (i.e. residual gas); gas pressure; inter-electrode gap; electrode material; electrode surface topography; type of voltage load; and position in the insulation system of an additional source of ion-electron pairs i.e. of the α-radiation Bragg peak. By a statistical analysis of experimentally obtained statistical samples of the random variable breakdown voltage (dc and impulse), it has been established that the transition from gas to vacuum breakdown mechanism takes place in a relatively broad region, in which the gas breakdown mechanism of an anomalous Paschen type and the avalanche mechanism of vacuum breakdown are present simultaneously.

► Transition from the gas breakdown to the vacuum breakdown mechanism is considered. ► Experiments are performed with dc and impulse voltage load. ► Additional source of ion-electron pairs is positioned in the insulation system. ► Transition from gas to vacuum breakdown mechanism takes place in a broad region. ► Anomalous Paschen effect and vacuum avalanche mechanism are present simultaneously.