Marx generator

About: Marx generator is a research topic. Over the lifetime, 1276 publications have been published within this topic receiving 8970 citations.

Microsecond Electron Beam Diode Closure Experiments

Abstract: : Experiments have been conducted on the Michigan Electron Long Beam Accelerator (MELBA) to explore diode closure and voltage compensation during collapsing diode impedance. MELBA operates with parameters: Voltage = - 0.6 to -1.0 MV; Current 60 kA; and Pulselengths exceeding 1 micro s. A reverse charged ringing circuit compensates the Marx generator output voltage to within +/- 7 % (+/- 10%) for pulselengths of 1 micro s (1.4 micro s) in a 127 ohm resistive load. Electron beam generation experiments have utilized two types of field emission cathodes: carbon brush and velvet cloth. Total electron beam pulselengths of 4 micro s have been achieved.

New model for ultracompact coaxial Marx pulse generator simulations

Abstract: This article describes a new simulation model developed with PSPICE in order to improve the ultra compact Marx generators designed at the French-German Research Institute of Saint-Louis (ISL) The proposed model is based on a Marx elementary unit and is an equivalent electric circuit that matches the actual configuration of the generator It consists of a structural description of the elementary stage of a Marx generator including stray components It also includes a behavioral model of the spark gap switches based on the Vlastos formula determining the arc resistance value The prebreakdown delay is also taken into account Experimental data have been used to validate the results of the simulations An original indirect measurement, allowing the estimation of the spark gap resistance, is also proposed

Development of high voltage step-up transformer as a substitute for a Marx generator

Abstract: A new type of pulse transformer has been developed as a substitute for a Marx generator. In the transformer amorphous metallic cores are utilized with windings of cylindrical conductors. As a result, low leakage inductance is realized with high breakdown strength. The coupling coefficient of the transformer is estimated to be more than 0.99. By using the transformer of winding ratio of 1:3, a Blumlein pulse forming line of capacitance 20 nF is successfully charged up to 270 kV by using a capacitor bank of 240 nF, 90 kV. High speed charging of charging time=250 ns is realized with high efficiency of energy transfer (energy transfer efficiency from the capacitor bank to the pulse forming line was evaluated to be 76%).

Synchronizable, injection‐locked, Q‐switched, mode‐locked, and cavity‐dumped ten‐atmosphere CO2 laser

Abstract: A novel, active, mode‐locking scheme for producing single, line‐tunable, high‐power ultrashort CO2‐laser pulses is described. Using an auxiliary grating‐tuned cw CO2 laser for injection locking on the 9R(16) line, the Q‐switched, mode‐locked, and cavity‐dumped 10‐atm CO2 laser produces single, detection‐limited (<500 ps) pulses of 5‐mJ energy at λ=9.29 μm. Details are given on the traveling‐wave GaAs Pockels cells, both of which are controlled by a single, ultraviolet (UV) triggered spark gap. The time‐locked output pulse is delayed by precisely 300.7 ns with <±50 ps jitter against the UV triggered spark gap, so the laser pulse is synchronizable to an external event to <±250 ps. To drive the transverse‐electric (TE) 10‐atm amplifier section, instead of the conventional Marx bank or inductance‐capacitance (LC) generator, a new type of circuit is used. The automatically preionized, double‐sided LC inversion circuit uses only one spark gap, and a detailed description with operating characteristics is provided.

ZR Marx capacitor vendor evaluation and lifetime test results

Abstract: The Z machine at Sandia National Laboratories (SNL) is the world's largest and most powerful laboratory X-ray source. The Z Refurbishment Project (ZR) is presently underway to provide an improved precision, more shot capacity, and a higher current capability. The ZR upgrade has a total output current requirement of at least 26 MA for a 100-ns standard Z-pinch load. To accomplish this with minimal impact on the surrounding hardware, the 60 high-energy discharge capacitors in each of the existing 36 Marx generators must be replaced with identical size units but with twice the capacitance. Before the six-month shut down and transition from Z to ZR occurs, 2500 of these capacitors will be delivered. We chose to undertake an ambitious vendor qualification program to reduce the risk of not meeting ZR performance goals, to encourage the pulsed-power industry to revisit the design and development of high- energy discharge capacitors, and to meet the cost and delivery schedule within the ZR project plans. Five manufacturers were willing to fabricate and sell SNL samples of six capacitors each to be evaluated. The 8000-shot qualification test phase of the evaluation effort is now complete. This paper summarizes how the 0.279/spl times/0.356/spl times/0.635-m (11/spl times/14/spl times/25-in) stainless steel can, Scyllac-style insulator bushing, 2.65-/spl mu/F, <30-nH, 100-kV, 35%-reversal capacitor lifetime specifications were determined, briefly describes the nominal 260-kJ test facility configuration, presents the test results of the most successful candidates, and discusses acceptance testing protocols that balance available resources against performance, cost, and schedule risk. We also summarize the results of our accelerated lifetime testing of the selected General Atomics P/N 32896 capacitor. We have completed lifetime tests with twelve capacitors at 100 kV and with fourteen capacitors at 110-kV charge voltage. The means of the fitted Weibull distributions for these two cases are about 17 000 and 10 000 shots, respectively. As a result of this effort plus the rigorous vendor testing prior to shipping, we are confident in the high reliability of these capacitors and have acquired information pertaining to their lifetime dependence on the operating voltage. One result of the analysis is that, for these capacitors, lifetime scales inversely with voltage to the 6.28/spl plusmn/0.91 power, over this 100 to 110-kV voltage range. Accepting the assumptions leading to this outcome allows us to predict the overall ZR system Marx generator capacitor reliability at the expected lower operating voltage of about 85 kV.