A Megavolt Nanosecond Generator with a Semiconductor Opening Switch

A high-current nanosecond-pulse generator with a pulse power of up to 1.6 GW, an output voltage of 0.5–1 MV, pulse duration of 40–60 ns, and repetition rates of 300 Hz (in a steady-state mode) and up to 850 Hz (in a burst mode) is described. Its average output power is 30 kW at a pulse repetition rate of 500 Hz. The energy-switching system of the generator fully consists of solid-state elements: a thyristor, magnetic switches, and a semiconductor-opening switch based on SOS diodes.     

A high-current pulse generator for gas discharge pumping

A generator has been designed for pumping a pseudospark gas discharge in xenon with the aim of generating UV radiation at a wavelength of 13.5 nm. The output parameters of the generator are as follows: the pulse energy is 10 J, the voltage is 6 kV, the peak current when short circuited is 40 kA, the base current pulse duration is 200 ns, and the frequency is as high as 500 Hz.     

High-frequency pulse generators based on SOS diodes with subnanosecond current cutoff time

Compact high-voltage generators with a pulse power of 100–500 MW, an output voltage of 150–400 kV, a pulse duration of 3–6 ns, and pulse repetition rates of 300–400 Hz and up to 5 kHz in a steady-state and a 30-s-long burst mode, respectively, are described. The output power-amplification unit is based on an inductive storage and SOS diodes with subnanosecond current cutoff time. Physical processes in the semiconductor structure of a SOS diode operating in the subnanosecond current cutoff mode are considered. The generator circuit designs and their test results are presented.     

A high-voltage semiconductor rectangular-pulse generator for powering a barrier discharge

A semiconductor rectangular-pulse generator with smoothly controlled output parameters for powering a barrier discharge was developed and investigated. The generator allows the formation of voltage pulses with the smoothly regulated amplitude (0–16 kV) and duration (600 ns–1 ms) across the discharge gap. The pulse rise and fall times can be varied from 40 ns to 1 μs. The generator pulse repetition rate can be smoothly varied from 0 to 50 kHz. The generator can operate in the manual-triggering mode and in the mode of pulse trains with an effective frequency of up to 500 kHz. The generator is intended for initiating and investigating a barrier discharge in millimeter-wide air gaps at the atmospheric pressure.     

A nanosecond SOS generator with a peak power of 4 GW

A high-current nanosecond generator with a peak power of up to 4 GW, an output voltage of 0.4–1 MV, a pulse duration of 8–10 ns, and pulse repetition rates of 300 Hz in a continuous mode and up to 1 kHz in the burst mode is described. The average output power at a pulse repetition rate of 1 kHz reaches 30 kW. The generator has an all-solid-state energy-switching system. A semiconductor opening switch on SOS diodes forms output pulses. The electric circuit and design of the generator are described, and the experimental results are presented. A device for eliminating prepulses across the load is proposed. The results of its testing and numerical simulation are presented.     

Installation for air cleaning from organic impurities by plasma formed by barrier discharge of nanosecond duration

A prototype installation for air cleaning by plasma, which consists of a barrier-type discharge reactor and a high-voltage nanosecond-pulse supply generator, which is based on drift step recovery diodes, is considered. A stable corona-type barrier discharge was obtained at a 3-kHz supply-pulse repetition frequency. The discharge remained nonlocalized even at a small gas-discharge gap (∼6 mm) due to a short (∼25 ns) pulse duration, which allows a quite uniform effect on the air flow. The high rise rate (∼6 kV/ns) of the applied supply voltage pulses determines the high voltage amplitude (∼25 kV) at the reactor at the breakdown moment and allows maintenance of high electric-field intensity and a high intensity of plasma chemical processes. Thus, an electrical power lower than 8 W is required at the reactor input to produce 1 g of ozone per hour. The concentration of methylmercaptan in air during waste-water smell deodorizing at State Unitary Enterprise “Vodokanal of St. Petersburg” was reduced down to an allowable level of 0.5 mg/m³ at the electrical power consumption no higher than 0.25 W per cubic meter of air.     

Nanosecond square high voltage pulse generator for electro-optic switch

A scalable square high voltage pulse generator, which has the properties of fast rise time, fast fall time, powerful driving capability, and long lifetime, is presented in this paper by utilizing solid state circuitry. A totem-pole topology is designed to supply a powerful driving capability for the electro-optic (EO) crystal which is of capacitive load. Power MOSFETs are configured in series to sustain high voltage, and proper driving circuits are introduced for the specific MOSFETs configurations. A 3000 V pulse generator with ~49.04 ns rise time and ~10.40 ns fall time of the output waveform is presented. This kind of generator is desirable for electro-optic switch. However, it is not specific to EO switch and may have broad applications where high voltage fast switching is required.     

A SOS-Generator for technological applications

A solid-state nanosecond SOS-generator for electrophysical technology applications is described. In the input part of the generator, the energy arrives at the high-voltage magnetic compressor through IGBT modules and a step-up pulse transformer. The input part of the generator is equipped with an unused energy recuperation circuit, and, when the output pulse is formed, the microsecond pumping mode of the semiconductor opening switch (SOS) is realized. As a result, the complete efficiency of the generator operating into a matched load is increased from ∼40 to 60–62%. The other characteristics of the generator are as follows: the peak voltage is up to 60 kV, the current is up to 6 kA, the pulse duration is about 40 ns, the pulse repetition rate in the continuous mode is 1 kHz, and the average output power is up to 9 kW.     

Reversible, high-voltage square-wave pulse generator for triggering spark gaps

A design is presented for a reversible, square-pulse generator that employs coaxial cables for charge storage and pulse formation and a thyratron as the switch. The generator has a nominal output voltage of 5-30 kV and a pulse duration determined by the cable's physical length. Two variations are presented: (1) a single-stage one consisting of cable that is charged via its shield on one end and discharged with a thyratron on the opposite end and (2) a two-stage one having an inverting circuit that uses a coaxial cable to reverse the polarity of the pulse. The generator operates with "flying shields," i.e., high-voltage pulses also propagate on the outside of the cables; this calls for a dedicated insulation that avoids breakdown between sections of the cable's shield. The rise time obtained is mostly dictated by the switching time of the thyratron; with the one we used in the tests, rise times in the range of 30-40 ns were obtained. We present the results obtained in the implementation of the generators as well as its application to fire a large Marx generator.     

A high voltage pulsed power supply for capillary discharge waveguide applications

We present an all solid-state, high voltage pulsed power supply for inducing stable plasma formation (density ～10(18) cm(-3)) in gas-filled capillary discharge waveguides. The pulser (pulse duration of 1 μs) is based on transistor switching and wound transmission line transformer technology. For a capillary of length 40 mm and diameter 265 μm and gas backing pressure of 100 mbar, a fast voltage pulse risetime of 95 ns initiates breakdown at 13 kV along the capillary. A peak current of ～280 A indicates near complete ionization, and the r.m.s. temporal jitter in the current pulse is only 4 ns. Temporally stable plasma formation is crucial for deploying capillary waveguides as plasma channels in laser-plasma interaction experiments, such as the laser wakefield accelerator.     

Generation of electron beams with adjustable durations of 1.0–0.2 ns and current amplitudes more than 400 A

The conditions for forming subnanosecond electron beams with adjustable pulse durations in the vacuum-diode mode using a SLEP-150 generator were investigated. It was confirmed that the residual air pressure in the diode (～0.1 Torr or less) does not affect the amplitude and duration of the beam current when using a nanosecond voltage pulse. It was shown that increasing the air pressure in the diode from 0.1 to 6.0 Torr leads to a decrease in the full width at half-maximum (FWHM) duration of the electron-beam current from ～1.00 to 0.18 ns and a shorter delay of the beam generation moment relative to the voltage-pulse rise time. It was established that the amplitude of the first peak of the beam current behind the foil remained constant under these conditions. Its value was ≥400 A. It is shown that when the interelectrode gaps are optimal for vacuum diodes, the pulse duration at elevated pressures shortens due to the gap breakdown for a time of ≤200 ps.     

A generator of high-voltage nanosecond pulses with a subnanosecond rise time

A generator of high-voltage pulses of nanosecond duration with a subnanosecond rise time is described. The generator contains a nanosecond-pulse shaper based on an assembly of drift step-recovery diodes (DSRDs) connected in series and a sharpening switch based on an assembly of deep-level dynistors (DLDs) connected in series. The results of tests of this generator at a pulse repetition rate of 100 Hz are presented. Voltage pulses with an amplitude of 20 kV, a rise time of 0.3 ns, and a duration of 10 ns are formed across a load with a resistance of 50 Ω.     

Formation of High-Power Pulses of Nanosecond Duration by Generators on Reverse Switch-on Dynistors with Sharpening Circuits Based on Diode Opening Switches

The basic principles of constructing generators of nanosecond pulses on reverse switch-on dynistors with sharpening output circuits based on diode opening switches are considered. The results of an experimental study of a high-power generator incorporating such a dynistor; a step-up pulse transformer; and a high-voltage diode opening switch, which is an assembly of drift step-recovery diodes connected in series, are presented. The output voltage pulses of the generator with an amplitude of 45 kV, a duration of 50 ns, a rise time of 10 ns, and a repetition rate of 1 kHz are applied to a load resistance of 25 .     

A high-power pulse amplifier for radar and navigation systems

A high-power pulse amplifier intended for pulse excitation of microwave generators on 3A750, 3A762, 3A765, and 3A766 diodes is described. An advantage of the amplifier is that its output voltage is independent of the load resistance owing to a low output resistance of ～0.05 Ω. The performance characteristics of the amplifier are as follows: a maximal output voltage of 120 V, a maximal output pulse current of 25 A, a pulse rise time of 10 ns, amplified-pulse durations of 20 to 300 ns, and a gain of 35 dB.     

High-voltage pulsed generator for dynamic fragmentation of rocks

A portable high-voltage (HV) pulsed generator has been designed for rock fragmentation experiments. The generator can be used also for other technological applications. The installation consists of low voltage block, HV block, coaxial transmission line, fragmentation chamber, and control system block. Low voltage block of the generator, consisting of a primary capacitor bank (300?μF) and a thyristor switch, stores pulse energy and transfers it to the HV block. The primary capacitor bank stores energy of 600 J at the maximum charging voltage of 2 kV. HV block includes HV pulsed step up transformer, HV capacitive storage, and two electrode gas switch. The following technical parameters of the generator were achieved: output voltage up to 300 kV, voltage rise time of ～50?ns, current amplitude of ～6?kA with the 40?Ω active load, and ～20?kA in a rock fragmentation regime (with discharge in a rock-water mixture). Typical operation regime is a burst of 1000 pulses with a frequency of 10 Hz. The operation process can be controlled within a wide range of parameters. The entire installation (generator, transmission line, treatment chamber, and measuring probes) is designed like a continuous Faraday's cage (complete shielding) to exclude external electromagnetic perturbations.     

Bipolar high-repetition-rate high-voltage nanosecond pulser

The pulser designed is mainly used for producing corona plasma in waste water treatment system. Also its application in study of dielectric electrical properties will be discussed. The pulser consists of a variable dc power source for high-voltage supply, two graded capacitors for energy storage, and the rotating spark gap switch. The key part is the multielectrode rotating spark gap switch (MER-SGS), which can ensure wider range modulation of pulse repetition rate, longer pulse width, shorter pulse rise time, remarkable electrical field distortion, and greatly favors recovery of the gap insulation strength, insulation design, the life of the switch, etc. The voltage of the output pulses switched by the MER-SGS is in the order of 3-50 kV with pulse rise time of less than 10 ns and pulse repetition rate of 1-3 kHz. An energy of 1.25-125 J per pulse and an average power of up to 10-50 kW are attainable. The highest pulse repetition rate is determined by the driver motor revolution and the electrode number of MER-SGS. Even higher voltage and energy can be switched by adjusting the gas pressure or employing N(2) as the insulation gas or enlarging the size of MER-SGS to guarantee enough insulation level.     

A high-frequency semiconductor generator of high-voltage nanosecond pulses

A generator of high-voltage rectangular nanosecond pulses equipped with switches in the form of assemblies of deep-level dynistors connected in series is described. A control circuit for dynistors based on an assembly of inversely switched-off diodes connected in series is considered. The generator can operate at a frequency of 10 Hz and form (at a 20-pF load) rectangular voltage pulses with short (4 ns) leading and trailing edges and a short (25 ns) delay relative to an external control signal. The amplitude and duration of output pulses are controlled smoothly in the ranges 7–9 kV and 100–600 ns, respectively. The spread of moments of operation is within 0.5 ns.     

A compact, low jitter, nanosecond rise time, high voltage pulse generator with variable amplitude

In this paper, a compact, low jitter, nanosecond rise time, command triggered, high peak power, gas-switch pulse generator system is developed for high energy physics experiment. The main components of the system are a high voltage capacitor, the spark gap switch and R = 50 Ω load resistance built into a structure to obtain a fast high power pulse. The pulse drive unit, comprised of a vacuum planar triode and a stack of avalanche transistors, is command triggered by a single or multiple TTL (transistor-transistor logic) level pulses generated by a trigger pulse control unit implemented using the 555 timer circuit. The control unit also accepts user input TTL trigger signal. The vacuum planar triode in the pulse driving unit that close the first stage switches is applied to drive the spark gap reducing jitter. By adjusting the charge voltage of a high voltage capacitor charging power supply, the pulse amplitude varies from 5 kV to 10 kV, with a rise time of <3 ns and the maximum peak current up to 200 A (into 50 Ω). The jitter of the pulse generator system is less than 1 ns. The maximum pulse repetition rate is set at 10 Hz that limited only by the gas-switch and available capacitor recovery time.     

A Multichannel Automatized System for Measuring Current Pulses in the LIA-30 Electron Accelerator

In the LIA-30 high-power linear pulsed induction electron accelerator (40 MeV, 100 kA, 25 ns), the energy is stored, and pulses of the accelerating voltage are shaped by 288 water-insulated radial lines arranged in succession along a common air-free acceleration channel. The lines are simultaneously charged up to 500 kV from 72 shielded Marx generators. To measure the parameters (amplitude, pulse shape, pulse rise time, pulse fall time, and pulse duration) of the synchronized pulses of the charging current with amplitudes as high as 60 kA and duration of 0.85 s in each of the 72 charging circuits, an automatized measuring system is used. The current pulse is sensed at the output of each generator by a self-integrating Rogovsky coil galvanically isolated from the generator. The signal from the coil is transmitted over a cable to an analog-to-digital converter, sampled with a period of 50 ns, and recorded in memory. Upon operating the accelerator, the signals are reproduced in succession or selectively on the display screen, and their shapes are compared to the shape of a standard pulse.