Showing papers on "Marx generator published in 1996"

Mobile X-ray unit

Abstract: A portable X-ray unit, of a relatively light-weight, occoping a volume of less then one-half a cubic foot containing an x-ray head assembly, a unique Marx generator, a plurality of spark-gap switches and control electronics is disclosed. The Marx generator allows for the development of a relatively high voltage in excess of 100 kV, yet allows for the discharge thereof within the nanosecond range. The Marx generator is enclosed by an acrylic insulator that cooperates with an aluminum enclosure, which functions as a return current path for the capacitors in the Marx generator and also as a shield against the escape of electromagnetic radiation from the pulsed x-ray unit. The Marx generator and spark-gap switches are confined within the pressurized chamber that may contain nitrogen gas to reduce the separation of the gap in the spark-gap switches.

Vacuum-spark metal ion source based on a modified Marx generator

Abstract: The plasma-generating parts of ion sources including their power supplies are usually floated to high potential (ion extraction voltage), thus requiring great insulation efforts and causing high costs for high-energy ion beams A new concept for pulsed ion sources is presented in which a single power supply is used to simultaneously produce the plasma and high extractor voltage via a modified Marx generator Proof-of-principle experiments have been performed with high-current spark discharges in vacuum where multiply charged ions are produced with this Marx-generator-based ion source ("Magis") Using "Magis", it has been demonstrated that pulsed ion beams of very high energies can be obtained with relatively low voltage For copper, ions of charge states up to 7+ have been found whose energy was 112 keV for a charging voltage of only 10 kV

The performance of a simple PFN Marx generator

Abstract: The performance of a 5-stage pulse forming network (PFN) Marx generator is described. Each stage of the generator was constructed from HV co-axial cable instead of discrete inductors and kV capacitors. The output voltage pulse from the generator is rectangular in profile, with a risetime of /spl sim/30 ns and a duration of /spl sim/100 ns. The maximum output voltage is 200 kV and the output impedance is 125 /spl Omega/. Due to the relatively small amount of energy stored in the device (/spl sim/10J), it may be operated at pulse repetition frequencies of /spl sim/100 Hz.

A PFN high voltage Marx generator

Abstract: This paper describes the construction and performance of a five stage, pulse forming network (PFN) Marx generator which has been constructed with commercially available HV coaxial cable. The coaxial cable has been used to replace the discrete HV inductors and capacitors which normally make up each stage. This approach to PFN Marx generators results in a system which is relatively straightforward to assemble, compact and inexpensive. The PFN Marx generator is suitable for moderate to low energy applications, such as general HV testing of capacitive loads and high speed triggering and it can be employed as an X-ray generator or microwave generator power supply. Although the stored energy in the generator can be quite modest, the device can be operated at high pulse repetition frequencies if required.

Two-Side Electron Beam Pumping System For Hundred-Joule-Level KrF Excimer Laser

Abstract: The pulsed power system for the "Heaven-1" hundred-joule-level KrF excimer laser is described The design of the pulse forming line, bifurcated pulse transmission lines and large-area diodes is summarized and the experimental results are presented The diodes can steadily operate at 650 kV and the behavior of diode impedance is studied at the diode voltage ranging from 400 to 650 kV The energy transmission efficiency from the Marx generator to the diales reaches 75%, and the total electron born energy arrives at ￣22 kJ for the 1300kV Marx generator voltage A hundred-joul-level KrF excimer laser is pumped from two sides by the electron beams provided by this Pulsed power system

Development of an X-band magnicon amplifier for the Next Linear Collider-cold cathode experiments and a thermionic design study

Abstract: Summary form only given. The Naval Research Laboratory has been studying the operation of an 11 GHz frequency-doubling magnicon amplifier driven by a -650 kV, 225 A, 5.5-mm-diam. electron beam produced by a velvet cathode driven by a single-shot Marx generator. The magnicon circuit consists of a set of 5.56 GHz TM/sub 110/ deflection cavities (a drive cavity, two gain cavities, and a two-section /spl pi/-mode penultimate cavity) containing synchronously rotating modes that spin the beam up to high transverse momentum, followed by an 11.12 GHz TM/sub 210/ output cavity that uses a synchronously rotating mode to decelerate the electrons and generate microwave radiation. In the design, the electron spin-up develops progressively Through the deflection cavities. In the experiments, a plasma saturation effect was observed that limits the circulating power in each of the gain cavities to <10 kW. In order to overcome this low field saturation, the experiment was operated near the instability point of the penultimate cavity. We have designed a new thermionic magnicon experiment, incorporating an advanced high-convergence electron gun to produce a 500 kV, 200 A, 2-mm-diam. electron beam, an improved deflection cavity design, and an improved output cavity that employs side-coupling to extract the RF power through a pair of X-band waveguides separated by 135/spl deg/ around the azimuth of the cavity without destroying the symmetry of the rotating quadrupole mode. The predicted efficiency is /spl sim/60%.

Hull Lecture No. 3 Marx-Like Generators and Circuits

Abstract: Two useful versions of Marx generators will be briefly described in these notes, untriggered and triggered.

X-ray spots emitted in a hollow cathode nanosecond discharge

Abstract: A 1 J-70 kV Marx generator triggers a discharge in a hollow cathode-pointed anode geometry. The X-ray emission is recorded by an intensified camera having 5 ns opening time. Small spots are observed either on the anode or on the insulator and their vicinity. The intensity is measured by means of a calibrated PIN diode. The spectral composition is determined using metallic foils as absorbers. The emission intensity and its duration varies with the pressure. The maximum intensity is obtained at 0.1 mbar for a 5 ns pulse.

Inductive line energy storage generator

Abstract: Inductive energy storage (IES) generator has long been considered to be the most efficient system for energy usage in large pulsed power system in the MA level. A number of parameters govern the efficiency of energy transfer between the storage capacitors and the load, and the level of current deliverable to the load. For high power system, the energy storage capacitors are arranged as a Marx generator. The primary constraints are the inductances in the various parts of the circuit, in particular, the upstream inductance between the Marx and the POS, and the downstream inductance between the POS and the load. In this paper, we consider the effect of replacing part of the upstream inductance with a transmission line and introduce the new concept of an inductive line for energy storage (ILES). Extensive parametric scans have been carried out on circuit simulations to investigate the effect of this upstream transmission line. A model is developed to explain the operation of the ILES design based on the data obtained. Comparison with an existing IES generator shows that the ILES design offers a significant improvement in the maximum current and hence energy delivered to an inductive load.

Optical photography of the magnetically confined anode plasma source for repetitive intense ion beam generation

Abstract: Summary form only given. Time resolved photographs of the visible light from the Magnetically Confined Anode Plasma (MAP) source for Ion Beam Surface Treatment (IBEST) are presented. The MAP source utilizes a fast (2 /spl mu/s rise time) magnetic field to create a plasma in a radically injected disc shaped gas puff and subsequently inject this plasma into the accelerating gap of a l0-cm-radius high power pulsed extraction ion diode. The 600 kV, 10 kA, 100 ns duration pulse for the beam is generated by a marx generator, cable feed, and linear induction voltage adder. The application of this technology is the generation of repetitively pulsed ion beams for government and industrial treatment of metal and polymer surfaces. Photographs of the MAP plasma were taken with an IMACON framing camera along the radial, axial, and azimuthal directions with a variety of gases and gas puff timings, using exposures as short as 10 ns. The photographs show a wealth of complex <1 mm luminous structures in the plasma.