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The Dual Axis Radiographic Hydrodynamic Test Facility (DARHT) was constructed at Los Alamos National Laboratory as a radiographic facility to provide two-axis multi-time radiography to support the US Stockpile Stewardship Program. The DARHT 1st Axis has been operational since 1999 and has been providing excellent radiographs. The DARHT 2nd Axis construction project was completed in early 2003. However,...
This paper presents a detailed two-dimensional model for high-voltage air-cored pulse transformers of two quite different designs. A filamentary technique takes magnetic diffusion fully into account and enables the resistances and self and mutual inductances that are effective under fast transient conditions to be calculated. Good agreement between calculated and measured results has been obtained,...
Burst RF fields (BRFFs) were applied to Chinese Hamster Ovary (CHO) cells, and the cell response to the BRFF of two different frequencies, 20 kHz and 50 MHz, was investigated by means of the fluorescent microscopy. The field strength and duration of the BRFF were fixed at 1 kV/cm, and 100 mus, respectively. Cells were placed in a 100 mum-gap electrode plated on the slide glass for a microscopy. Acridine...
Gas discharge sterilization techniques have some principal merits as compared to conventionally used methods. Among them the following ones should be mentioned: low temperatures of sterilization, high efficiency, low energy consumption, low cost and simplicity of equipment maintenance. For wide practical applications the diffuse gas discharge of nanosecond duration excited in highly nonuniform fields...
A combination of electromagnetic topology (EMT) and a transmission line matrix methodology to simulate an external electromagnetic pulse's interactions with cable network following penetration through apertures is presented. The results show improvements over previous simulations using EMT technique only. An array of the topological network has been created by the integration of the sub-network matrices...
The need for inexpensive, disposable, single use, ultra- compact, pulsed power devices has increased dramatically over the past few years. This is driving the development of extremely small pulsed power devices constructed from off-the-shelf components. However, the majority of readily available electronic components are designed and characterized only for long life use such as batteries. HEM Technologies...
We present the results of an experimental research effort focused on developing a compact, low jitter, command triggered, high peak power, high pulse repetition rate (PRR), gas-switched pulse generator system. The pulse generator is command triggered by a single TTL level pulse generated by a control system implemented using software and a computer interface card. The TTL trigger pulse fires a solid-state...
The ZR z-pinch driver is being upgraded to deliver 26 MA into a standard load, a substantial increase compared to the present Z maximum of 20 MA into the same standard load. The upgraded accelerator has basically the same foot print as the existing Z, thus bringing a number of challenges, one of the critical ones being the insulator stack. The present stack is formed by 4 levels, the top two with...
An annular form factor dry film capacitor having the minimum possible equivalent series inductance (ESL) has been developed for short pulse applications requiring high currents at voltages below 10 kV DC. The annular design offers the lowest possible inductance at the system level and can be wound to a tolerance of plusmn1%. The narrow film width provides a low equivalent series resistance (ESR) and...
As to a wide range of pulsed power application, data concerning electrical insulation play a basic role, and breakdown has not been studied in detail for the repetitive nanosecond-pulses conditions. Breakdown characteristics of rod-plane gas gaps were investigated with repetitive burst conditions under variant repetition rates and diverse gap distances respectively. The experimental results show that...
This paper documents the testing results of the ZR prototype 600-kV mini-Marx trigger generator (MTG) and polyurethane barrier samples from four suppliers. Our goal was to qualify alternative suppliers as future sources of the dielectric interface barriers. The approach was to raise the electric fields on the polyurethane/water interface until surface tracks, or flashovers, occurred and compare the...
This paper outlines the advantages of photonically-switched power electronics from the standpoint of robustness to electromagnetic interference (EMI) effects, design-ease, and system reliability. Subsequently, the principles of operation of two novel superjunction-based heterostructure optically-triggered devices are described. Satisfactory performance results of the two devices address three critical...
Numerous dielectrics have been developed for various high-voltage high-power microwave applications. The primary goals for HPM insulation are to provide adequate insulation over the lifetime of the device, provide high dielectric strength at low volume and weight, and function with minimal maintenance and ancillary components. Current testing methods for dielectric materials are antiquated processes...
Summary from only given. The capabilities of the Z accelerator will be significantly enhanced by the Z Refurbishment (ZR) project [McDaniel DH, 2002]. The performance of a single ZR module is currently being characterized in the pre-production engineering evaluation test bed, Z20 [Lehr, JM, 2003]. Z20 is thoroughly diagnosed so that electrical performance of the module can be established. Circuit...
The University of Missouri Terawatt Test Stand (MUTTS) has conducted many untriggered experiments on a Rimfire gas switch scaled to 2.5 MV. The focus of these experiments was to evaluate what methods may be used to control the distribution of cascade arcs. The untriggered data indicates that the rise time of switch current does not statistically improve, as expected, as the number of cascade arcs...
A simple phenomenological model is described for calculating spark-gap resistance in nanosecond gas discharges. Initially an existing model is described, which involves the density and composition of the gas in which the spark-gap is immersed and the radius of the expanding channel. The model is then extended, using conductivity values fitted to experimental data. The accuracy of the model is validated...
A model of a spark gap used as a shorting switch in a Blumlein pulsed power system has been developed. The spark gap is a gas-filled switch that is triggered by an ultraviolet laser pulse. Methods of reducing the rate at which the resistance of the arc falls are the focus of this investigation. The model consists of two separate parts: a kinetic model, which shows the formation of the plasma streamer,...
The Z refurbishment project is designed to increase the peak current to the load on Z to ~26 MA in a 100-ns wide power pulse. This current is achieved by summing the current from 36 independent pulse-power modules. To meet these requirements, we have designed and constructed an SF6-insulated gas switch that can hold off 5.5 MV and conduct a peak current of 600 kA for over a hundred shots. The gas...
We report results of studies of a small pseudospark and back-lighted thyratron (BLT) switch, operating with currents >4 kA, and hold off >20 kV. The switch was operated in an optically triggered mode (BLT) with helium fill for >106 pulses, with 0.5 mC transfer per pulse, at a repetition rate of 10 Hz without significant decay of switch performance. Additional studies with gases including...
A multi-gap multi-channel (MGMC) switch of 500 kV has been developed at Pohang Accelerator Laboratory (PAL). It consists of ten of gaps to increase self-discharge voltage by filling up the gas. A structure of a multi-gap switch can increase its inductances. Thus, in order to solve those problems its structure made by multi-channels had been designed to decrease the inductance effects. The fabricated...
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