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This paper proposes a compact pulse generator for NOx removal application for diesel automotive. The rising time is important factor to increase NOx removal efficiency in pulsed corona discharge method. Manufacturing cost and compactness of the pulse power generator should be satisfied for automotive application. The proposed pulse power uses a low voltage thyristor, a pulse transformer with the function...
In this paper, the measurement and analysis of shockwaves generated by pulsed discharge in water are made with FUJI pressure measuring film. When pressure is applied, the reaction takes place between the color-forming material and color-developing material coated on the bases of the film, and color corresponding to the level of pressure is generated. Based on these results the energy transferred to...
We designed and developed a portable high-voltage pulse generator for microplasma applications. The prototype pulse generator is powered by four AAA batteries and in a palmtop size utilizing an inductive energy storage technique. The open output voltage is 3.5 kV and the repetition frequency ranges from 0.5 to 1.7 kHz. It successfully worked to produce the microplasma with needle-to-sphere miniature...
Very compact pulsed power systems can be fabricated with stacked Blumlein lines (SBL). The critical component necessary to field a viable SBL system is the switch that is integrated into one of the two transmission lines that forms each Blumlein in the stack. The critical parameters of the switch are the current inductive time constant, the switch resistive phase closure time, and the switch closure...
Pulsed power hydrodynamics experiments typically involve multi-megajoule capacitor banks, imploding thin-walled cylinders of solid- density metal by the electromagnetic force associated with axial currents in excess of ten megamperes. Much of this activity operates with technology developed for other applications (e.g., soft X-ray generation), which can be significantly larger than actually required...
This paper presents the computational analysis of an experimental three-layer liner system, Al-polyethylene-Cu and Al-water-Cu, designed for the study of dynamic strength of low-density and high-density materials using the perturbation growth caused by the Rayleigh-Taylor instability. Copper and polyethylene dynamic strength models developed by VNIIEF are used. Comparison between computations and...
This paper discusses a novel multiple-switch pulsed power technology. By using transmission lines, multiple switches can be synchronized like in a MARX generator. To gain insight into this technology, an equivalent circuit model was developed, a two-switch experimental setup and a prototype pulsed power source with four gas spark- gap switches have been constructed. The four-switch setup includes...
The klystron-modulator (K&M) system of the Pohang Light Source( PLS) had been supplying high power microwaves for the acceleration of 2.5 GeV electron beams since October 2002. There are 12 sets of K&M systems to accelerate electron beams to 2.5 GeV nominal beam energy. One module of the K&M system consists of an 80 MW S-band (2856 MHZ) klystron tube and the matching 200 MW modulator....
The current project is to build an electron gun for X-ray free electron laser (XFEL) application. The electron gun will utilize field emission and extreme accelerating gradient to achieve very low emittance. However for long-term study of cathode characteristics, a stable pulsed voltage in the megavolt range is needed. The first project phase is to design and test a 500 kV pulser using a resonant...
For the industrial-scale electroporation of sugar beets the use of a set of synchronized, hence triggered, Marx-generators promises an energy-efficient processing. Such generators need to operate during a seasonal campaign of 100 days without interruption. In order to obtain some experience in the possible problems of the design, a long- term test is performed. The following issues are considered...
This paper proposes new structure of a high speed high-voltage pulse power generator with a saturable pulse transformer and high-voltage diode stack as a semiconductor opening switch. To reduce the leakage inductance, a linear pulse transformer structure is proposed consisting of a ferromagnetic core having one- turn primary winding and one-turn secondary winding. Each primary winding is connected...
PIM is a water filled Blumlein connected in parallel to one or two 1.5 MV cavities, which inductively add voltage on a high impedance (100 Ohm) vacuum transmission line. A negative polarity rod pinch diode was tested on this 1-3 MV IVA pulse power machine and an investigation into the performance of this radiographic diode was made. Time and spatially resolved investigations into the radiating target...
A non-linear vertical GaAs photoconductive switch with device dimensions of 27004times630times1 microns and diagonally opposed palladium contacts was used. The primary material used in the photo-switches is Liquid encapsulated Czochralski (LEC) grown GaAs, in which deep donors are compensated by shallow acceptors. The anode was heated to a temperature of 330 K. The devices were analyzed in terms of...
High resistivity SiC has been shown to be a viable PCSS material [1]. High breakdown field, extreme thermal stability, wide energy band-gap, crystal robustness, and large electron saturation velocity are likely to make devices made from SiC more reliable under extreme operating conditions [2]. Because of its limited use this far, there is a need to study and characterize a SiC PCSS as a viable component...
Over the past 30 years, the paraxial diode has utilized a gas-filled transport cell to focus an electron beam onto a high-Z target in order to generate intense x-rays for flash radiography. One of the key objectives is to create a small radiographic spot, which in turn is related to the focusing dynamics of the beam. For gas-filled transport cells, the primary limitation to achieving a small time-integrated...
In this paper, application of carbon nanotube coated cold cathodes for high-voltage, high-current, plasma switches for pulsed power applications is reported. We have fabricated and characterized a pseudospark switch with a carbon nanotube coated cold cathode as an electron beam source for controlling the switch. The demonstrated cold cathode triggered pseudospark switch is free from severe thermal...
Tests validating the consistency and repeatability of controlled electrical surface flashover on metallized thin film insulators were performed. The study of electrical surface flashover has been mainly confined to its prevention under various contaminated conditions such as ice. The experiments discussed in this paper have gone in the opposite direction. The focus of the experiments was not to prevent...
An electrical breakdown model for liquids in response to a sub-microsecond (~ 100 ns) voltage pulse is presented, and quantitative evaluations carried out. It is proposed that breakdown is initiated by field emission at the interface of pre-existing micro-bubbles. Impact ionization within the micro-bubble gas then contributes to plasma development, with cathode injection having a delayed and secondary...
Cylindrical type air core pulse transformers capable of passing high voltage and energy pulse waveforms with high efficiency and low distortion require a much more delicate design balance of physical dimensions and electrical parameters than iron or ferrite core units. The structure of an air core high voltage pulse transformer is relatively simple, but considerable attention is needed to prevent...
In this paper we present results of a current measurement in a wire liner of a facility for soft X-ray radiation pulses formation. The measurements were held with a magneto-optical method using Faraday effect in a single-mode fiber. It is shown that using magneto-optical method it is possible to measure the current more than 100 MA with a current rise time of ~1014-1015 A/s. These values are almost...
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