Picosecond semiconductor generator for capacitive sensors calibration

Abstract

The paper describes a semiconductor picosecond pulse generator that can be used to calibrate capacitive high voltage sensors of MV range. The generator is designed as a base unit, to which external pulse converters are connected. In the base unit, semiconductor devices – first a semiconductor opening switch (SOS) and then a semiconductor sharpener (SS) – generate an output pulse with a rise time of 220 ps and a subsequent flat-top of 2 ns in duration. The pulse amplitude is around 1 kV across 50 Ω load. An external diode sharpener generates a pulse with 120 ps rise time and 500-ps flat-top at the amplitude of 850 V. To switch the semiconductor sharpeners to the conducting state, the shock-ionization wave mode is used. Additional pulse converters make it possible to generate output pulses across 50 Ω load with the rise time of 70-150 ps, the pulse duration of 135-310 ps, and the amplitude of 130–480 V. The electrical diagram of the generator and waveforms of the output pulses are presented. An example of the calibration of capacitive sensors of a multi-gigawatt picosecond generator is also shown.