Development and Evaluation of Electrooptical High-Voltage Pulse Measurement Techniques

Use of the Kerr electrooptical effect for time-resolved pulse measurements is extended to the 300-kV level. Pulse durations are as short as 5 μs. The performance of systems equipped with Kerr cells of various designs is investigated under a variety of operating conditions. Calibrations are achieved using both pulse-divider and high direct-voltage techniques. Methods are devised for measurement and correction of errors resulting from the fringing electric field at the ends of the Kerr-cell electrodes. Measurements of the temperature coefficient of the Kerr-cell constant are also included. The pulse waveform is reconstructed from typical Kerr-system results by automatic computation and compared with simultaneous time-resolved pulse-divider measurements. Comparisons at the peak of the pulse, where a "slideback" technique is used to enhance the resolution of the divider measurement, demonstrate agreement to better than 1 percent. In addition, a novel technique is developed for measurement of the pulse magnitude from photographs of the Kerr-effect fringe patterns produced by passing an expanded, pulsed laser beam through the system. By this approach, voltage is measured optically without use of sophisticated electrical metering instrumentation.