Linearizations of statistical time delay of breakdown in a semi-logarithmic plot as a function of relaxation time at working voltagesU_w= 315, 345, and 375 V at inter-electrode distancesd= 1, 1.5, and 2 cm, glow currentI_g= 130 μA, and pressurep= 200 Pa, respectively (symbols are experimental data and lines are analytical fits of Eq. (4)).