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

A high-frequency generator of high-voltage nanosecond pulses based on an assembly of drift step-recovery diodes is described. A circuit that includes parallel transistor chains for the formation of forward and reverse currents of drift diodes is presented. The results of tests of this generator are presented. Voltage pulses with an amplitude of 2.5 kV, a duration of 2 ns, and a pulse repetition rate of 300 kHz were obtained across a 50-Ω load.     

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.     

A high-power semiconductor switch of high-voltage pulses with a rise time of nanosecond duration

The results of studies of new fast-acting semiconductor devices—deep-level dynistors intended for use in high-power devices of nano-and microsecond pulsed-power technology—are presented. The possibility of switching multikiloampere current pulses having a rise rate of 200 kA/μs with the use of a single device with a 12-mm-diameter structure is shown. A high-power switch based on an assembly of dynistors with an operating voltage of 12 kV connected in series is described. The switch is capable of switching current pulses with a 1200-A amplitude and a 4-ns rise time.     

Semiconductor formers of high-voltage pulses of nanosecond duration

A small former of high-voltage pulses of nanosecond duration based on new semiconductor devices—deep-level dynistors (DLDs)—is described. The former has been developed on the basis of the Marx voltage-multiplication principle and allows formation of 8-kV voltage pulses across an 8-Ω load at a 2.5-kV input-voltage level. A DLD-based former with an output diode opening switch based on assemblies of drift step-recovery diodes connected in series is described. The results of its being tested are presented. Voltage pulses with an amplitude of 25 kV and a rise time of 1 ns are obtained across a 100-Ω load.     

Operation simulation of a high-voltage nanosecond multistage generator

A model of a high-voltage nanosecond multistage generator employing series voltage addition in the transmission line with stepwise adjustment of the wave impedance is described. The forming lines are coaxial to the transmission line. The generator contains three arrays of switches which are brought into operation one-by-one with a delay equal to the time in which the electromagnetic wave propagates between them, thus forming across a 2.5-kΩ load a pulse whose amplitude is five times higher than the charge voltage of the forming lines. The calculated generator efficiency on an 8.4-Ω matched load is 95%.     

A compact high-voltage nanosecond marx generator based on air-field dischargers

Results of the development and study of a 14-stage air high-voltage pulse generator with an output voltage of up to 250 kV, a current rise time of 10 ns, and blow capacitance of 400 pF are presented. The design and the schematic circuit diagram of the generator are described.     

A high-voltage nanosecond pulse generator based on a barrier discharge

One of the specific features of the barrier electric discharge is the short duration of microdischarge processes that last about tens of nanoseconds. A high-voltage nanosecond pulse generator based on a barrier electric discharge is presented. A voltage of tens of kilovolts is usually applied to electrodes of the discharge cell. The peak values of the current pulse may be very high (from a few amperes to several tens of amperes). The presented high-voltage nanosecond pulse generator, having a sufficiently simple design, ensures quite good pulse repetition stability, and, when necessary, allows one to easily tune characteristics of pulses and their repetition rates by changing the geometrical, electrical, and physical-chemical parameters of the setup.     

Low-pressure gas-discharge current interrupters in a generator of high-voltage nanosecond pulses with an inductive energy storage

Designs of grid units with slotted and multiple-aperture configurations of holes that allow an increase in the stability of the current-cutoff process and a reduction in the time to turn the device off in a high-voltage pulse generator with an inductive energy storage were created. Compared to a TGI2-500/20 thyratron, these designs made it possible to reduce the time instability of the instant of the current interruption by factors of 2 and 5 for switches with the multiple-aperture and slotted configurations of the grids, respectively. These constructions allowed the minimum time for disabling a device to be reduced by 25%.     

Optimization of high-voltage devices for energy compression of nanosecond pulses

Designs of compact converters intended for compression of high-voltage pulses with durations of a few nanoseconds and operating in a traveling wave mode were examined. The energy compression unit contained two lines-high-impedance and forming-with a high -pressure gas spark discharger used as a switch. A traditional serial connection of lines was replaced by a parallel connection to increase the energy compression efficiency. The power of the initial pulse (amplitude, 145 kV; half-height duration, 4 ns; and rise time, 1.5 ns) at a load of 45 Ω was increased by a factor of 1.8, while the calculated value was 2.5. The amplitude was as great as -195 kV, and the power was 17% higher relative to the circuit with a serial connection of lines. When shaped, the pulse was compressed in time to 0.8 ns. Two modifications of devices converting the initial pulse with an amplitude of -160 kV and a rise time of 0.3 ns into pulses with amplitudes of -210 and -250 kV and durations of 0.80 and 0.45 ns, respectively, were tested. Waveguide components of the converters were developed, with which it was possible to minimize the dimensions of the device in order to avoid excitation of higher harmonics while maintaining the electric strength.     

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 compact repetitive high-voltage nanosecond pulse generator for the application of gas discharge

Uniform and stable discharge plasma requires very short duration pulses with fast rise times. A repetitive high-voltage nanosecond pulse generator for the application of gas discharge is presented in this paper. It is constructed with all solid-state components. Two-stage magnetic compression is used to generate a short duration pulse. Unlike in some reported studies, common commercial fast recovery diodes instead of a semiconductor opening switch (SOS) are used in our experiment that plays the role of SOS. The SOS-like effects of four different kinds of diodes are studied experimentally to optimize the output performance. It is found that the output pulse voltage is higher with a shorter reverse recovery time, and the rise time of pulse becomes faster when the falling time of reverse recovery current is shorter. The SOS-like effect of the diodes can be adjusted by changing the external circuit parameters. Through optimization the pulse generator can provide a pulsed voltage of 40 kV with a 40 ns duration, 10 ns rise time, and pulse repetition frequency of up to 5 kHz. Diffuse plasma can be formed in air at standard atmospheric pressure using the developed pulse generator. With a light weight and small packaging the pulse generator is suitable for gas discharge application.     

A generator of high-power nanosecond pulses based on a modular two-level summator

A modular approach to designing generators of high-power high-voltage nanosecond pulses on the basis of a two-level wave summator and transistor formers of partial pulses is considered. The design and parameters of the modules that are oriented at the development of generators of voltage pulses of up to 300 kV at a current of up to 4 kA are described. The capabilities of these modules are demonstrated based on the example of a pulse generator with a power of 10 MW, a varied pulse duration of 50–150 ns, and a pulse repetition rate of up to 2 kHz.     

A high-voltage nanosecond pulse generator for exciting diffuse gas discharges at atmospheric pressure

A high-voltage nanosecond pulse generator intended for studying diffuse discharges in gases at pressures close or equal to atmospheric pressure is described. The generator produces pulses with an ∼50-ns (at half-height) duration, a >50-kV voltage amplitude, a 10- to 12-ns rise time, and a pulse repetition rate of up to 1 kHz across an equivalent load (1.3 kΩ, 15 pF). The generator is based on available cheap components, and the amplitude (energy) of output pulses and their repetition rate can be promptly regulated in a wide range. The generator is immune to noise and reliable.     

一种诱导肿瘤细胞凋亡的多参数可调高压纳秒脉冲发生器

为了研究纳秒脉冲电场诱导肿瘤细胞的凋亡效应及其窗口参数选择规律,本文结合脉冲功率技术和Blumlein集中参数LC网络脉冲形成线原理,研制出了一台医用多参数可调、便携式、智能型高压纳秒方波脉冲发生器。该发生器主要由高压直流电源、纳秒脉冲形成系统和脉冲整形及计数系统三部分组成,输出脉冲幅值4～15kV连续可调,脉宽50～500ns可变,上升沿最小10ns,重复频率可调,治疗时间窗口可控,并具有液晶显示和保护功能。以人浆液囊腺性卵巢癌SKOV3为研究对象,正交设计出多种脉冲参数组合进行实验分析,探索出肿瘤细胞凋亡率较高的脉冲治疗窗口参数。医学实验表明:发生器紧凑、轻便、性能稳定,有效满足了纳秒脉冲电场诱导肿瘤细胞凋亡的机理及窗口参数选择的研究需要。     

A high-voltage stable-pulse generator

A high-voltage pulse generator producing pulses with a stable flat top is described. It is based on a multistage amplitude discriminator with inductance coils. The generator produces pulses with an amplitude of up to ?20 kV, a top width of up to 200 μs, and a pulse repetition rate of up to 50 Hz at a 20-kΩ load. The top width voltage instability does not exceed ±20 V. The generator is used in the power supply system of the INR linac H^? injector-based ion source.     

A compact nanosecond pulse generator

A compact high-current pulse generator with the amplitude of the load current up to 140 kA and rise time below 200 ns is designed. The basic element of the pulse generator design is the HCEIcap 100–0.2 capacitor switch assembly. The capacitance value of the capacitor switch assembly is 200 nF, the charging voltage is 100 kV, the energy storage is 1000 J, and the full inductance value is 20 nH. The sizes of the active part of the capacitor are 80-mm inner diameter ×160-mm outer diameter ×160 mm. A multigap spark-gap is used as a switch. The rise rate of the current through the load (X-pinch, 2 molybdenum wires with a 25-μm diameter) is 1.3 kA/ns, and the soft X-ray pulse duration is 2.0–3.5 ns.     

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.     

Investigation of the electrical strength of liquid dielectrics in vacuum under the action of high-voltage nanosecond pulses

The results of an experimental study of the electrical strength of insulators that are coated with a thin liquid-dielectric layer (1?C2 mm) are presented. Studies were performed in a vacuum at a pressure of 10^?4?C10^?5 Torr and a high-voltage pulse duration of ??100 ns on an experimental setup, which is based on a PG-1 high-voltage nanosecond generator with an output voltage of up to 500 kV at a load of up to 40 ??. It was established that a castor or transformer oil coating on an insulator allows an increase in the amplitude of a voltage pulse, which is applied to the insulator, by a factor of at least 1.7 as compared to the clean insulator without its breakdown over the surface in vacuum.