Showing papers on "Marx generator published in 2022"

High Voltage Pulse Generator Based on a Novel Magnetic Isolated Drive Circuit

Abstract: In order to meet the requirements of high voltage, high power, and compactness for pulse generators used in the field of liquid food sterilization, an all-solid-state Marx generator based on a novel magnetic isolated drive is proposed. The drive circuit uses the magnetic core to transfer the control signal, which adopts core stacking and inverse paralleled secondary side winding. It only needs one drive signal to realize synchronous conduction of the main switch or bypass switch and the complementary conduction of both. The maximum pulse width of drive signal is not limited by the magnetic core saturation. The topology is simple, and the problem of high voltage isolated drive of Marx generator is solved. Based on the novel magnetic drive, a 31-module solid-state Marx generator is built and a prototype test is carried out. The test results show that the maximum instantaneous power of this generator is 1.3 MW (30 kV, 43 A) with a pulse width of 3–10 μs and an adjustable repetition frequency of 0–1 kHz.

High-Voltage Repetitive Nanosecond Pulse Generator Utilizing Power Synthesis of Modified Avalanche Transistorized Marx Circuits

Abstract: In order to further improve the output voltage amplitude and repetitive operation reliability of nanosecond pulse generator (PG) based on avalanche transistor (AT), the method of power synthesis of modularized Marx circuits with transmission line transformer (TLT) is employed in this article. The modified positive $4\times11$ -stage Marx circuit introducing base-triggering method is designed and implemented to improve the operation reliability. The triggering synchronization and the consistence of output characteristics of multiple Marx modules with an identical trigger pulse are validated. The feasibility of combining pulses generated from four Marx modules with an optimized four-stage TLT is demonstrated. The influences of the type and quantity of magnetic core and the superimposed stage number of TLT on the output performance of the generator are investigated. The operation characteristics of the generator including output parameters, trigger time-delay, and loop efficiency in the whole working range are evaluated. The experimental results show that the working range of the overall device has been widened significantly with the injection of additional initial carrier. Accordingly, the generator prototype is capable of achieving the output performance with an adjustable voltage amplitude in the range of 7.8–26.7 kV on a matched 300- $\Omega $ resistive load and 12.2–38.9 kV on the high-resistance load, respectively, a 10%–90% rise time of 3.6 ns, and a full-width at half-maximum (FWHM) of 12.2 ns. A long-term test with the maximum repetition rate of 3 kHz is conducted to realize high-voltage output and high-frequency operation simultaneously.

Research on the Bipolar Microsecond Pulse Generator Using the Multistage Resonant Charging

Abstract: In this article, a bipolar pulse generator based on multistage resonant charging has been proposed, which can deliver microsecond-range pulses for medical and industrial applications. The main circuit consists of two sets of identical Marx generators connected back to back with the load between them. It can flexibly output bipolar pulses with adjustable amplitude, pulse width, and frequency. In this research, six eight-stage Marx generators have been employed to verify the performance of the proposed bipolar pulse generator. From the experimental results, the proposed generator can deliver pulses with the amplitude of ±10 kV to no-load and a resistive load of 50 $\text{k}\Omega $ . The repetitive frequency can be adjusted from 1 Hz to 1 kHz, and pulse width can be adjusted from 0.2 to $400~\mu \text{s}$ with 50 ns rising and falling time. The relaxation time between the positive and negative pulses can be determined from 0.2 to 400 $\mu \text{s}$ . In the high-voltage field, the proposed Marx generator can deliver higher output voltage pulses and has smaller voltage differences between stages than the traditional solid-state Marx generator.

Marxiplier: An Innovative Marx-Based Single-Source Multilevel Inverter With Voltage Multiplying Capability

Abstract: This article proposes a novel single-source high step-up asymmetrical multilevel inverter (MLI) topology based on Marx generator configuration with voltage multiplying capability. The operating principles of the proposed converter (which is named Marxiplier) are completely different from the MLIs presented in the literature. Proposed converter uses a low-voltage dc source with high-frequency inverter (low-voltage ac input) and charges a series of capacitors multiple times of input voltage. These capacitors which work as asymmetrical sources can generate a high-amplitude ac output voltage with high number of levels. Another important aspect of this converter is producing negative levels in the output voltage without using a high-voltage full-bridge inverter and reducing the number of the components. MATLAB simulations and a laboratory test results of a 21-level prototype are employed in order to verify the proposed converter operation.

A Mini-Marx Generator Powered by a Cockcroft–Walton Voltage Multiplier

Abstract: A Marx generator generates a high-voltage (HV) pulse by charging two or more capacitors in parallel and then suddenly connecting them in series. In principles, a comparatively lower voltage dc power supply has to be used for the charging to achieve the desired HV. However, a moderate dc HV power supply is still quite expensive and bulky but not in full-time usage. In this work, a mini-Marx generator powered by a Cockcroft–Walton (CW) voltage multiplier has been proposed to form a more efficient, compact, but affordable configuration of pulsed HV power sources. For generating an HV in a range of 20–150 kV with the mini-Marx generator consisting of eight stages, a CW multiplier operating up to 3–20 kV is required. Numerical simulations using PSpice have been performed for validating the concept. For demonstration, a prototype of the 22-stage CW-powered four-stage mini-Marx has been built and tested with an ac voltage of 110 V at 60 Hz. In the experiment, the CW generator can reach 3.6 kV to power the mini-Marx, delivering an HV of 12.7 kV, consistent with the PSpice modeling. With an ac household voltage of 220 V at 60 Hz, a dc voltage of 5.2 kV can be obtained from the CW to charge an eight-stage mini-Marx generator, achieving an output voltage of 33 kV to drive a field emission-based X-ray source. The proposed CW powered mini-Marx generator is general and can be used as a compact pulsed voltage supply for some portable devices.

Investigation of an Axial Virtual Cathode Oscillator with an Open-Ended Coaxial Cathode

Abstract: A cathode with an open-ended coaxial structure is experimentally investigated using an axial virtual cathode oscillator (vircator). To enhance the microwave power output, an open-ended coaxial cathode is installed in the axial vircator. The proposed cathode is designed based on the reciprocating frequency of the vircator. The operation features of an axial vircator with a solid cathode, an annular cathode, and an open-ended coaxial cathode are comparatively analyzed through simulations and experiments. Three cathodes are machined using graphite. A stainless steel mesh with a transparency of 70% is used as an anode. The anode-to-cathode gap is fixed to 6 mm. The vircator is driven using a 10-stage PFN-Marx generator with a characteristic impedance of 31 Ω. The PFN-Marx generator applies -150 kV voltage pulses with a 170–200 ns pulse width into the vircator. The microwave power from the solid and annular cathodes is 11.22 MW and 11.27 MW, respectively. The proposed cathode generates a microwave with a power of 12.65 MW while enhancing the microwave power by 13% compared with the solid and annular cathodes. The proposed cathode shows a frequency shift to 3.4 GHz, which is a much lower frequency than that of the solid cathode at 6.34 GHz.

A 10kV Modular Solid Boost-Marx Pulse Generator With Inductive Isolation

Abstract: Solid-state Marx pulse generators are widely used in biomedical electroporation, food processing, and plasma material modification. It uses parallel charging of energy storage capacitors and series discharging to achieve high-voltage pulse output. However, the isolation resistance used to charge the energy storage capacitor seriously affects the generator's charging speed and overall efficiency during high-frequency pulse output. In this paper, an inductor is selected as an isolation device in a traditional solid-state Marx circuit. And only add a switch in the circuit to form a solid-state boost-Marx pulse generator (BMPG). The added switch is equal to the voltage level of each module in the circuit. The output pulse amplitude is several times, and the efficiency is increased through the use of energy during the charging and discharging of the inductor. The proposed circuit retains the Marx circuit's advantages in simple structure, stability, reliability, and modularization and improves the output pulse gain and parameter control flexibility. It also reduces the input DC power supply requirement. When using 12 modules, the input DC voltage is only 235V, which can achieve 10kV high-voltage pulse output. The pulse voltage boost multiple can reach 42.5 times.

Fast capillary discharge device for soft x-ray generation in the “carbon-window” and “water-window” spectral regions

Abstract: Abstract The paper presents a compact source of soft X-ray radiation based on a fast capillary discharge developed for “water window” microscopy methods. The central part of the source is the specially designed nanosecond voltage pulse generator capable of operating at a frequency of 600 Hz, with 100 ns pulse duration and energy per pulse 5 J. The discharge is created in a borosilicate capillary non-uniformly filled with gas. The plasma emission spectra obtained for the case of source operation in argon-helium mixture demonstrate well-pronounced lines in the “carbon window” range, in carbon dioxide-lines in the “water window” range. An analysis of the emission spectra in the range of 2–9 nm in cases of different inlet gas pressures made it possible to estimate the degree of ablation of the inner wall of the capillary and to determine the suitable operating pressure range.

Development and Test of a 500-kV Compact Marx Generator Operating at 100-Hz PRF

Abstract: This article presents the electrical and mechanical design of a compact 13-stage 0.5-MV Marx generator operating at a pulse repetition frequency (PRF) of 100 Hz. The fast-switching process of the generator is based on spark gaps, operated under pressurized air and leading to the generation of an output pulsed voltage with a peak of 0.5 MV and a rise time of 15 ns when operated on a 300- $\Omega $ load. Corona-stabilized electrodes are installed near the main gap of the switches to improve their operational stability and increase the PRF. To ensure compactness, the Marx generator is housed in a cylindrical metal vessel with a height of 92 cm and an outer diameter of 34 cm, having a total volume of 74 L. A highly accurate simulation using both PSpice and CST software packages was used to predict the impulse waveform at the output of the generator and to help in optimizing the generator design. The tests show a good agreement between the experimental data and the theoretical predictions.

Analysis and Experimental Verification of the Peaking Capacitor’s Flashover Process in an EMP Simulator

Abstract: The flashover process of the peaking capacitor in the electromagnetic pulse (EMP) simulator is studied based on theoretical analyses and experimental verification in this paper. There are deeper and denser ablation spots on the film surface near the inner core of the destroyed peaking capacitor, while the damage of the outer film is relatively slight, which indicates that the flashover current along the inner film is larger. Besides, the circuit simulation analyses show that the earlier the flashover occurs on the film of the peaking capacitor, the smaller the flashover current. The electric field on the non-conical surface of the capacitor is mainly occupied with normal component. Differently, for the conical surface, the electric field on the outer layer is dominated by the normal component and the parallel component is the main part on the inner layer. It is considered that the flashover on the conical surface originates from outer layers and develops gradually to the inner until the flashover penetrates through all layers. Furthermore, the images of flashover show that the flashover firstly occurs on the outermost layers and develops to the inner layers with the increase of the voltage. For such special structure of the peaking capacitor, the parallel component of electric field is more likely to facilitate the flashover under nanosecond pulse. These results may exhibit specific reference implication in the design of insulation for the peaking capacitor used in EMP simulator.

An efficient circuit design for nanosecond pulse generation for electroporation applications

Abstract: The application of high voltage, short duration electric pulses to the cell membranes and tissues increase their permeability by creating temporary pores within the cell membranes and tissues. It stimulates the delivery of extracellular materials into the cell, finding diverse applications in medicine for drug delivery and treatment of tumor. This phenomenon of physical transfection is known as electroporation. This paper presents an efficient circuit design for the generation of nanosecond pulses for electroporation applications. A Marx generator with two stages of insulated gate bipolar transistors (IGBT), resistors and capacitors are used in the proposed circuit in order to induce optimized pulses that produce enough electric field for obtaining high voltage across the load. In this circuit, high voltage (100V) nanosecond pulses are generated with different pulse width 10ns, 2ns and 1ns. By varying the number of IGBT stages, different nano second pulses can be generated for different applications of electroporation. The proposed design approach aims to produce controlled electric pulses in the nano-second range with reduced switching losses and harmonic distortion.

Research on a Novel Nanosecond Marx Generator and Its Efficiency Analysis

Abstract: The traditional Marx generators based on avalanche BJTs usually use a DC voltage source to charge the storage capacitors, and many theoretical studies have proved that the existence of DC voltage source leads to low energy efficiency. This paper proposes a novel nanosecond Marx generator based on avalanche BJTs, which is charged by a series-resonant power supply. This power supply charges all capacitors with a constant average current and all BJTs avalanche breakdown stage by stage without any triggering signals. When the resistors are replaced by inductors, the efficiency can be further improved. The pulse repetition frequency can be adjusted by controlling the resonant average current. The output voltage can be increased by connecting more avalanche BJTs in series or increasing the number of stages of the Marx generators. The control method and the structure of the circuit are simple. Experimental results show that negative pulses with an adjustable frequency of 10–60 kHz, a pulse width of 8.45 ns, and an amplitude of 4 kV were obtained on a resistive load. The energy efficiency of the Marx generator was increased to 94%.

Design of a Double Pulse Test Platform for Switching Devices

Abstract: The performance of switching devices has a great impact on the operating frequency and loss of power electronic circuits. Therefore, the working characteristics of the device are needed to be tested by double pulse test. However, the traditional double pulse test circuit has some disadvantages, such as high requirements for power drive capability, high cost and poor safety. Therefore, referring to the working principle of the Marx impulse voltage generator, this paper designs a double pulse test circuit platform with low charging requirements, low cost and good security. This paper verifies the reliability of the test platform by testing a GaN switching devices.

Multi-stage voltage droop compensation based on resonant circuit for unipolar solid-state Marx Generators.

Abstract: The low-voltage droop of high-voltage pulses is required to provide stable pulsed electric fields in many applications. Increasing the capacitance of energy storage capacitors increases both the size and the cost of the system. In this paper, four compensation stages based on the resonant circuit have been inserted into a 16-stage solid-state Marx generator to compensate for the voltage droop in different conditions. The nearly linear part of the sinusoidal voltage is precisely added to the load during discharging as compensation, and the rectangular pulsed voltage with little droop can be realized. Different numbers of compensation stages and different resonant inductances can compensate the droop to different levels, which means the compensation effect is also adjustable. Moreover, these compensation stages can operate as common stages in Marx generators as long as we open-circuit the resonant circuits. Since the capacitors in resonant compensation stages are also charged in parallel with capacitors in common stages, no auxiliary power supply is required. Simulating and experimental results show that the droop of a 9 kV pulse can be ideally compensated over a 500 Ω resistive load at various pulse widths. The pulse width should be shorter than the length of the nearly linear part of the sinusoidal voltage.

Optical Diagnosis of Preionization Mechanisms and Breakdown Characteristics in a Nanosecond Switch

Abstract: Megavolt-class pulsed gas switches play an important role in large pulsers as transfer switches. This article analyzes the breakdown process and characteristics of a megavolt self-triggered preionized switch under 100-ns pulses based on the optical diagnosis. It is discovered that the triggering spark illumination targeting the main cathode or anode can separately preionize the main gap. The discharge channel is likely to first form between trigger electrodes and the main anode. Based on the above deduction, the streamer velocity is calculated to be $0.54 \times 10^{6}$ – $2.34 \times 10^{6}$ m/s, proportional to the electric field. Also, parameters of the empirical formula for calculating the gas heating time are amended. Influence mechanisms of the switch jitter are also studied. Under pulsed preionization mode, the trigger gap breaks down when the main gap electric field is high enough, and the switch jitter is mainly determined by the self-triggering jitter. Nonetheless, the self-triggering jitter can be partly offset during the breakdown process if the changing rate of mean reduced electric field $d(E/p)$ / dt at the self-triggering time is higher than 1.0 $1.0\left(\mathrm{kV} \cdot \mathrm{ns}^{-1} \cdot \mathrm{cm}^{-1} \cdot \mathrm{MPa}^{-1}\right)$ . Under sustaining preionization mode, the trigger gap breaks down prematurely, and the continuous arcing driven by switch leak current preionizes the main gap. Therefore, the influence of the self-triggering jitter on the switch jitter can be eliminated.

Gate Drive Power Supply with Low Insulation Voltage Transformer for in-vehicle Marx Circuit

Abstract: This paper proposes a gate drive circuit with a low-insulation voltage transformer for an in-vehicle Marx circuit. The Marx circuit will be used for NOx gas decomposition for diesel vehicles as a part of an ozonizer. In order to make the Marx circuit on board, it is necessary to reduce the size and cost of the circuit, including the gate drive circuits. One of the bottlenecks for lowering the cost and size of the gate drive circuit is the insulation transformers on the gate drive circuits because the potential of each switch of the Marx circuit dynamically changes from zero to the output voltage of the Marx circuit. This paper proposes and demonstrates the gate drive circuit, which receives the drive power for the MOSFET on the n-th stage from $(\boldsymbol{n}-\mathbf{1})$ -th stage through a low-voltage transformer. Due to the configuration, the required insulation voltage of the transformer is equal to the input voltage. In this paper, the design procedure of the transformer with an approximated current is described. The proposed gate drive circuit is developed and implemented to the 4-kV Marx circuit.

Publisher's Note: "Multi-stage voltage droop compensation based on resonant circuit for unipolar solid-state Marx Generators" [Rev. Sci. Instrum. 93, 114704 (2022)].

Abstract: First Page

The Generation of Intense-Relativistic-Microsecond Electron Beams From a High-Energy-Density Marx Generator With Waveform Modification

Abstract: Intense electron beams with pulse duration on the level of microseconds have been utilized in a number of areas, including the production of free electron laser, material surface modification, and high-energy-density physics research. The high-voltage pulse forming technology based on metal oxide varistors (MOVs) has been verified to be an effective way to produce quasi-square pulses in recent years. In this article, a high-energy-density Marx generator with output waveform modified by a flat-top compensation LC filtering branch and a low inductance MOV folding structure was designed and tested to generate microsecond pulses. Experimental results show that a quasi-square pulse with a voltage amplitude of more than 500 kV and a pulsewidth of $1~\mu \text{s}$ was obtained on a dummy load of $50~\Omega $ . Further experimental research was carried out using a magnetically insulated coaxial diode (MICD) electron beam diode, and as a result, a relativistic electron beam with an energy of 550 keV, a current of 8.3 kA, a rise time of less than 40 ns, and a flat-top of about 600 ns was produced. The Marx generator with a modified waveform has the advantages of simple design, compact construction, and high-quality flat-top, which is a good platform for the generation of intense microsecond electron beams.

Design of a Compact 1-MV-Class Radial Closing Switch for Tesla Type Generator

Abstract: The paper presents the development of a megavolt-class SF6-insulated radial switch. The switch is used as a crowbar in a MV Tesla-type generator to produce pulsed electric fields in very large volumes, for proof-of-concept experimentation of a novel non-invasive food processing technology. The main features of the switch include: (1) Using SF6 gas as the insulation gas; (2) a breakdown channel along the radial direction, rather than axial; (3) a compact configuration with its volume limited to 3.2 L. In order to achieve a ruggedized high voltage insulation as well as an enhanced operation safety, the following design techniques were applied: (1) Structures of the switch were well designed to minimize the local electric filed in the cathode triple junctions; (2) the grooves of surface of the insulators that enclose the switch were finely optimized to keep the surface flashover under control; (3) a prolate spheroid geometry of the high voltage electrode was adopted to achieve a better control of the gas breakdown. This paper describes in detail the design and the preliminary test of this switch.

Electric strength of dielectrics under influence of bipolar voltage pulses of submicrosecond duration

Abstract: The development of electric pulse technologies for the destruction of solids states (rocks) --- drilling, cutting and crushing requires reduction of high pulse voltages. In this work, for the first time, studies are proposed and carried out to determine the breakdown voltages of various dielectric media (air, water, rocks) while simultaneously supplying two pulses to the electrode system by two high voltage generators of different polarity --- positive and negative, which halves the operating impulse voltage each generator. In addition, experiments have shown that for all media there is a decrease in breakdown voltage in comparison with a monopolar voltage pulse, which reaches 28% --- for the breakdown of sandstone, 23% --- granite, 24% --- water, 25% --- air. A physical explanation of the discovered effect is given. Keywords: monopolar and bipolar pulse voltage, breakdown voltage, discharge channel.

Self-Powered Gate Drive Circuits With Optical Signal Isolation for In-Vehicle Marx Circuit of Ozonizer

Abstract: Reducing the cost of a Marx circuit as a high-voltage power supply for nitrogen oxide (NOx) decomposition for diesel vehicles is required. The Marx circuit with MOSFETs has an advantage in size compared to the Marx circuit with gap switches. However, the Marx circuit with MOSFETs needs gate drive circuits on the gate of each MOSFET. The gate signal and drive power must be supplied to each gate with isolation in a low-cost way. However, the transformer for the isolation with high withstand voltage, such as 10 kV or more, is typically high cost because of the low demand. This article proposes the self-powered gate drive circuit using the charging path of the Marx circuit. The proposed gate drive circuit only requires a low withstand voltage because the power for the MOSFET on the $n$ th stage is supplied from the ( $n -1$ )th stage via a low-voltage transformer. Besides, the gate signal is transmitted through pairs of LEDs and photodiodes instead of high-cost optical fibers. The proposed gate drive circuits are developed and implemented into a prototype of the Marx circuit with an output voltage of 4 kV. From the experiments, it is demonstrated that the proposed drive circuits provide both drive power and gate signal.

Dependence of Characteristics of Pressure Impulse Produced by Electrical Discharge in Water on The Risetime of the Applied Voltage

Abstract: The risetime of the voltage impulse applied to an electrode gap in water is known to have an influence on the behaviour of the oscillating bubble that forms in the subsonic breakdown regime, and hence on its acoustic emission characteristics. The paper presents a study on the influence of the voltage impulse risetime under the supersonic operation regime, where the breakdown is dominated by streamers, and hence the acoustic emission occurs via a completely different process. By varying the self-inductance along the transmission line connecting a fast pulsed power generator to the underwater acoustic source, high-voltage impulses with a peak reaching 100 kV and with risetimes between 10 ns and 300 ns are generated. The resultant pressure pulses are accurately measured using two hydrophones covering a large acoustic bandwidth. The paper will present the main data obtained, together with an analysis highlighting the existing correlations between the voltage rise time, the inter-electrode gap and the peak pressure generated. The insights gained during this study will facilitate the optimised design of a supersonic source generating powerful ultrasound.

Development of a high-power pulse-forming network Marx generator with a long pulse duration.

Abstract: To meet the application needs for producing long-pulse electron beams and high-power microwaves, a pulse-forming network Marx generator with a pulse duration of 260 ns is presented in this paper. This generator is composed of 20 stages of pulse-forming network modules. Each module is formed with nine capacitors connected in parallel. The generator functions at 44 kV, which is lower than the rated voltage of the mica paper capacitor, to improve the lifetime. The impedance of the generator is designed to reach 45 Ω. To avoid the strong coupling between the adjacent stages, the physical layout of the generator adopts a zigzag design. The generator is housed in a gas pressurized vessel of 600 mm in diameter and 580 mm in length. Across a 50 Ω load, it can deliver quasi-rectangular pulses with a pulse duration of 260 ns and an amplitude of 500 kV for a single shot. The output pulse features a plateau duration of 160 ns and a leading edge of 45 ns. In burst mode, it can steadily output ten pulses of 450 kV at a repetition rate of 10 Hz on either a resistive load or a diode.

A 500 kV, 10 kA, 40 ns coaxial Marx generator pulser for cable fed flash x-ray system.

Abstract: Flash x-ray (FXR) systems are used for dynamic radiography. Depending on the speed of the object, these systems typically require a very short pulse duration (∼25 ns) for image acquisition without motion blur. The conventional Marx generators with zigzag discharge paths result in higher inductance; hence, they do not meet the requirement of shorter pulse duration (30-40 ns) and low impedance (40-60 Ω) simultaneously. A coaxial Marx generator has been designed and developed, which is capable of generating 500 kV peak voltages and 10 kA peak current within a 40 ns pulse duration. The CST simulation of the coaxial Marx generator has been carried out to validate the design parameters. The FXR electron beam diode is powered by this Marx generator. Experiments were carried out to measure the x-ray parameters like pulse width, source size, x-ray energy spectrum, penetration depth, and cone angle. The maximum measured x-ray dose was 62 mR at 1 m distance from the source window. The x-ray radiograph demonstrates a penetration depth of 32 mm in steel kept at 2.5 m distance from the source for 500 kV diode voltages.

A portable flash x-ray generator powered by an explosive driven ferroelectric generator.

Abstract: In order to develop a portable flash x-ray source, a compact explosive pulsed power source based on an explosive-driven ferroelectric generator (EDFEG) is investigated numerically and experimentally in this paper. The EDFEG is used as a primary power supply to charge a pulse capacitor, and then the capacitor outputs high current through an inductor and an electrical exploding opening switch (EEOS). Finally, a high voltage fast pulse is generated on a diode, which generates x rays. A circuit model was built to analyze the performance of this compact pulsed power source. A portable flash x-ray generator prototype was constructed in our laboratory. The typical experimental results illustrated that after metal wires of the EEOS exploded, a high-voltage fast pulse with a peak value of 180 kV, a rise time of 2.8 ns, and a pulse width of 30 ns was generated on the x-ray diode. Meanwhile, an x-ray pulse with a pulse width of 19 ns, a focus of about 1 mm, and a dose of 100 mR at 15 cm was obtained.

Analysis of a Solid-State Switch as Peaking Switch in a Solid-State Marx Generator

Abstract: This paper discusses about the investigations on the performance of solid-state Marx generator with and without peaking circuits. Ten stages monopolar solid-state Marx generator (SSMG) is simulated in MATLAB and the results are validated mathematically. A three-stage prototype of the Marx circuit is implemented to analyse the delay associate with the switch control circuit. The output pulse rise time is compared with and without the peaking circuit. To attain the peaking action the minimum time required to turn-on the peaking switch is much smaller than the required turn on time of an IGBT switch. Fast switching solid-state devices are required to act as a peaking switch to attain both the peak voltage and reduced rise time.

Impedance Effects On Nonlinear Transmission Line Performance

Abstract: Nonlinear transmission lines (NLTLs) bring increased reliability and tunability to a market dominated by vacuum high-power microwave (HPM) sources [1] . Generally, NLTLs are driven by pulse forming circuits such as the Marx generator; however, recent efforts have successfully achieved RF formation by using the NLTL simultaneously as the pulse forming line (PFL) and as an HPM source [2] , substantially reducing the spatial footprint.