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Showing papers on "Marx generator published in 1986"


Journal ArticleDOI
TL;DR: In this paper, a high voltage pulse generator suitable for bipolar pulse testing of semiconductor devices is described, using field effect transistors as the switching elements in a multistage capacitor discharge circuit based on the Marx generator principle.
Abstract: The design and construction of a high voltage pulse generator suitable for bipolar pulse testing of semiconductor devices is described. The apparatus uses field effect transistors as the switching elements in a multistage capacitor discharge circuit based on the Marx generator principle.

12 citations


Journal ArticleDOI
TL;DR: In this paper, a softly focused KrF laser beam was employed to irradiate insulator SF6 gas through the rail gap along a 60 cm-long, highvoltage electrode with the power level of 5×107 W/cm2.
Abstract: Laser triggering of a SF6‐filled, 500‐kV rail gap is described. A softly focused KrF laser beam was employed to irradiate insulator SF6 gas through the rail gap along a 60‐cm‐long, high‐voltage electrode with the power level of 5×107 W/cm2. The rail gap was operated as the main switch of a 2.8‐Ω, 500‐kV Blumlein circuit, two of which drive the electron beam diodes to pump a 200‐J, 70‐ns KrF laser from both sides. Multichannel operation of the rail gap was obtained by the application of laser triggering with the result of reduced voltage fall time of 20 ns (10–90%) compared with 50 ns in the self‐breakdown mode. The jitter was also decreased to less than 2 ns in the trigger operation of the gap.

11 citations


Journal ArticleDOI
TL;DR: In this article, a modified Marx generator system is described in which each capacitor stage is insulated by an inductive cavity instead of by insulating dielectric eliminating most of the insulation volume and circuit inductance.
Abstract: We describe a modified Marx generator system in which each capacitor stage is insulated by an inductive cavity instead of by insulating dielectric eliminating most of the insulation volume and circuit inductance which are inevitable in the conventional Marx generator system. This feature permits use of this system as a fast pulsed power system of very high voltage by stacking a very large number of stages. Necessary relations needed for pulsed power applications are derived by a simple circuit analysis. Design parameters of a charged particle beam accelerator are given as an example illustrating the utility of this concept.

Proceedings ArticleDOI
21 Oct 1986
TL;DR: In this article, a 2 cm aperture X-ray preionized TEA CO laser was successfully operated, achieving an output energy of 12.6 % with an average dose of typically 50 mr/shot.
Abstract: A 2 cm aperture X -ray preionized TEA CO laserReinder J. ZuidemaTwente University, Department of Applied Physics,P.O. Box 217, 7500 AE Enschede, The NetherlandsAbstractA cryogenically cooled 2 cm aperture sealed -off UV or X -ray preionized TEA CO laser wassuccesfully operated. It was found that X -ray preionization performed better than UVpreionization. 17.5 J /R, output energy was extracted from a 2x2x40 cm3 discharge volume. Themaximum efficiency was 12.6 %.IntroductionThe CO laser is subject of a growing interest especially as a tool for materialprocessing and for medical applications. It has several advantages with respect to the CO2laser: a potential for higher efficiency, variable pulselength from several hundreds of psecto over 10 msec, and the wavelength between 5 -6 pm allows beam handling by means of fibers.Besides for medical applications this wavelength offers also more favourable absorbtionproperties.On the other side a self -sustained discharge CO laser is more difficult to operate,especially for large apertures. The reason is that for efficient operation the laser has tobe used at low temperatures. At these temperatures impurities are frozen out of the laser gasmixture so that sufficient preionization is difficult to achieve with an UV source. This isthe main reason for us to investigate X -rays as an alternative way of preionization. Thistechnique proved to be very succesful for RGH- lasersl and high -pressure CO2 lasers2'3. Wefound this technique to perform better in the case of a CO laser too.A cryogenically cooled 2 cm aperture sealed -off TEA CO laser was succesfully operated,using an X -ray preionization source. For reasons of comparison the laser was also operatedwith an UV preionization source. Using X -ray instead of UV preionization yielded an increasein output energy in the order of 20 %.The present work is an extension of our previous work on UV preionized TEA CO lasers4,where we obtained a maximum output energy of 625 mJ per pulse from a 1x1x18 cm3 dischargevolume with an efficiency of 11.4 %.System descriptionA schematic cross -section of the system is given in figure 1. The X -ray photons areformed in a 10 pm thick Ta -foil serving as the anode of a cold -cathode e -beam machine. A 50pm thick Ti -foil is serving as the exit window for these photons. The voltage is producedby a two -stage Marx generator equipped with two 40nF /50kV capacitors operating at a chargingvoltage of 35kV. The pulse length is in the order of 2 psec.The laser chamber essentially consists of two concentric stainless steel tubes withrespectively diameters of 20 and 24.5 cm, surrounded by 3.5 cm of insulating foam. The spacein between the tubes can be filled with liquid nitrogen. The inner tube contains the lasergas and the laser electrodes. The laser actually operates at 100K. The X -ray photons areentering the laser gas through a 50 um thick Ti -foil of the same dimensions as the exit foilof the X -ray source. Using a dosimeter located just behind this foil inside the laser chamberwe found an average dose of typically 50 mr /shot.The laser electrodes are profiled according to a publication of Chang5, with k = 0.02 andv = arccos( -k). The discharge dimension are 2x2x40 cm3. Mounted to this electrodes is asimple construction for UV production based on the corona discharge technique. A descriptionof this method can be found in a paper by Ernst6. Two 5 mm thick pyrex glass plates areused. When operating the laser with X -ray preionization, this construction is removed sothat the X -ray photons can freely enter the discharge volume. The electrodes are connectedto a two -stage Marx generator equipped with two 40nF /50kV capacitors by means of two low -impedance high -voltage feed -throughs separated by 22 cm. The total circuit inductance isabout 250 nH, resulting in a current pulse length of 0.20 psec FWHM.The optical cavity is formed by a flat 80% R /AR coated Ge outcoupling mirror and acurved Au- coated Al reflector with a radius of curvature of 5 m. These mirrors are sealingboth ends of the laser chamber. The outcoupling is nearly optimized. The total cavity length