Influence of radiation on the sparkover of sphere gaps and crossed-cylinder gaps stressed with impulse voltages

The influence of various forms of radiation on the sparkover characteristics of sphere gaps for 25, 50 and 75 cm-diameter spheres, and of crossed-cylinder gaps for 6.25 and 25 cm-diameter cylinders, has been studied when impulses of both polarities and waveshapes of 1/1000, 1/50 and 80/1000 ¿s are applied. Radiation improves the accuracy with which the characteristics of such gaps may be determined, and, to achieve an accuracy of better than 1% at all spacings at which each gap would normally be used for impulse-voltage measurement, it is recommended that a radiation source having a strength of the order of 10 mCi be used.