Breakdown delay time in phototriggered discharges

The breakdown delay times of phototriggered discharges have been measured and calculated for binary neon/xenon and neon/HCl mixtures as well as for the ternary neon/xenon/HCl mixtures used in XeCl lasers. The study has been performed for minor gas concentrations in the range 10 ppm–10% at total pressures up to 6 bars and for reduced electric fields between 4 and 40 Td. The agreement between the predicted values and the experimental results is quite good. The analysis of the results points out that the breakdown delay times are mainly determined by the direct ionization from the ground-state atoms and molecules, except when the reduced electric field and the concentration in minor gases have simultaneously low values. In such cases, the breakdown delay times are determined by the Penning effects. A transition between a resistive phase, dominated by the microscopic processes, and an inductive regime, which is circuit limited, is also reported.