Nanosecond and subnanosecond repetitive pulsed power systems

Abstract

Summary form only given, as follows. Pulsed power systems not allowing repetitive operation are commercially unusable. For one of the first repetitively operated nanosecond, high-current pulse accelerator (1968) with an electron energy of 500 keV, which was used to charge a pulse-forming line consisting of a Tesla transformer and gas-flow spark gaps, a pulse repetition rate of 100 Hz was achieved. Later this system was improved and repetitive pulse generators producing an average power of up to 10 kW at a pulse repetition rate of 1000 Hz and 100 kW at 100 Hz (Sinus 7) were developed. New possibilities for developing more powerful repetitive pulsed power systems emerged when opening switches based on semiconductor SOS diodes had been created (1992). If such a system is operated in a pulse train mode, the pulse repetition rate may reach 5 kHz. The highest achieved average power of this type of generator is 50 kW at a peak voltage of 1 MV. The physical capabilities of SOS diodes would allow a pulse repetition rate of 1 MHz; however, this high repetition rate is unattainable because of the long charging time of the system. Repetitive pulsed power systems (accelerators, microwave oscillators, X-ray generators, lasers, and the like) require for their operation, in addition to switches, proper cathodes in the diodes accelerating electrons. In this paper, repetitively operating cathodes for electron accelerator diodes, namely, conventional graphite and metal-dielectric cathodes using high-/spl epsiv/ ceramics and new metal-dielectric composite systems, are considered. The performance of an electrical insulation subject to the action of repetitive nanosecond pulses is also discussed.