Short Pulse Generators

The study of the SOS-diodes showed that the current interruption time decreased to 500-600 ps when the reverse pumping time was reduced to 10-15 ns. Figure 16 illustrates the stage of subnanosecond interruption of current equal to 1 kA. The current cutoff time is 600 ps.

Fig. 16.

Photograph in Figure 17 shows the subnanosecond opening switch having the working voltage up to 250 kV at 3 to 4 ns pulse width. It is about 110 mm long, and contains 2 parallel branches, each made up of 160 series-connected semiconductor structures. The surface area of the structure is 0.25 cm².

Fig. 17

The subnanosecond SOS diode served as the basis for development of two types short pulse generators [23, 31]. The first generator of SM-2NS type provides the output voltage of 150 to 250 kV, the full width at half maximum of 3 to 4 ns, the pulse power up to 100 MW, and the pulse repetition frequency up to 3 kHz. Visual appearance of the SM-2NS generator is shown in Fig. 18, and Table VI illustrates its specifications.

Fig. 18.

Table VI. Specifications of the SM-2NS generator

A more powerful generator of SM-3NS type offers the pulse power up to 500 MW at the pulse length of 5 to 6 ns, has the output voltage up to 400 kV, and operates at the pulse repetition frequency as high as 2 kHz. Table VII illustrates its specifications, and Fig. 19 shows output voltage waveform with an amplitude of 400 kV across 1.3 kOhm load resistance

Fig. 19.

Table VII. Specifications of the SM-3NS generator.