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Showing papers on "Marx generator published in 1985"


01 Jun 1985
TL;DR: In this paper, the Michigan Electron Long Beam Accelerator (MELBA) has been used to explore diode closure and voltage compensation during collapsing diode impedance, achieving pulselengths of 4 micro s (1.4 micro s).
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.

15 citations


Journal ArticleDOI
01 Jan 1985
TL;DR: In this paper, a modification of one of the typical Marx circuit configurations, i.e., the series connection of a sphere gap and an inductance to the tail resistance, is suggested to overcome this drawback.
Abstract: A substantial decrease in efficiency compared with the standard lightning impulse occurs in the production of very short-tailed lightning impulses by means of the Marx generator. A modification of one of the typical Marx circuit configurations, i.e. the series connection of a sphere gap and an inductance to the tail resistance, is suggested here to overcome this drawback. Digital simulation of the phenomena involved and extensive experimental work prove this solution to be suitable for the purpose.

6 citations


01 Jan 1985
TL;DR: In this article, the DEMON II Marx generator has been developed to achieve low erection time jitter and reliability in a multistage, bipolar Marx generator, while maintaining exceptionally low pre-fire rates.
Abstract: Multimodule pulsed power accelerators typically require high module reliability and nanosecond regime simultaneity between modules Energy storage using bipolar Marx generators can meet these requirements Experience gained from computer simulations and the development of the DEMON II Marx generator has led to a fundamental understanding of the operation of these multistage devices As a result of this research, significant improvements in erection time jitter and reliability have been realized in multistage, bipolar Marx generators Erection time jitter has been measured as low as 25 nanoseconds for the 32 MV, 16-stage PBFA I Marx and 35 nanoseconds for the 60 MV, 30-stage PBFA II (DEMON II) Marx, while maintaining exceptionally low prefire rates Performance data are presented from the DEMON II Marx research program, as well as discussions on the use of computer simulations in designing low-jitter Marx generators

5 citations


01 Jun 1985
TL;DR: The Mini Marx as discussed by the authors is a low-energy Marx generator designed at Los Alamos as a spark gap trigger and has been improved and is now manufactured commercially by Veradyne Corp. The Mini Marx was designed for ease of manufacture from the outset.
Abstract: : A low-energy Marx generator was designed at Los Alamos as a spark gap trigger. Since the initial report1 the design has been improved and is now manufactured commercially. The Mini Marx has a risetime of less than 2 ns to over 200 kV measured in to a 23 omega load. The power output approaches one gigawatt. The Mini Marx can multichannel field distortion gaps or fire a number of gaps with little gap-to-gap isolation. It has also been used to power a small X-ray tube. The Mini-Marx shown in Fig. 1 is now manufactured commercially by Veradyne Corp. The Mini Marx was designed for ease of manufacture from the outset. Its commercialization is a good example of technology transfer from a National Laboratory to private industry. The Mini Marx should have an excellent sales future since its output characteristics are better than other more expensive and complicated units on the market.

5 citations


01 Jan 1985
TL;DR: Aurora as mentioned in this paper is an inertial confinement fusion laser system using optical angular multiplexing and a chain of four cold cathode electron beam driven KrF laser amplifiers to produce 10 to 20 kJ of optical energy.
Abstract: : Aurora is an inertial confinement fusion laser system using optical angular multiplexing and a chain of four cold cathode electron beam driven KrF laser amplifiers to produce 10 to 20 kJ of optical energy The electron guns make use of graphite felt cathodes that range in emission area from 1,200 cm2 to 20,000 cm2 and are typically driven by Marx generator charged waterline PFLs of 27 omega impedance that produce 650 ns pulses when switched by SF6 insulated trigatrons Typical cathode voltages are 300 kV to 700 kV with cathode current densities of 15 to 25 A/cm2 Electron current is transported to the laser gas through metal foil or Kapton windows and a hibachi support structure Magnetic guide fields of 18 to 30 kG are used for beam guidance In this paper, we will concentrate on the major electron gun components of these amplifiers: Marx generators, water PFLs , output switches, feedthrough bushings , cold cathode diodes , and magnets All of the Aurora e-guns are similar , except that the SAM does not employ a PFL and the LAM uses two electron guns, each driven by two PFLs in parallel The design and performance of the electron guns are described in more detail in the sections that follow

4 citations


Journal ArticleDOI
TL;DR: In this paper, a sixteen beam, heavy ion injector is designed at Los Alamos National Laboratory (LANL) to demonstrate the injector technology for the High Temperature Experiment (HTE) proposed by Lawrence Berkeley Laboratory.
Abstract: Design and development of a sixteen beam, heavy ion injector is in progress at Los Alamos National Laboratory (LANL) to demonstrate the injector technology for the High Temperature Experiment (HTE) proposed by Lawrence Berkeley Laboratory. The injector design provides for individual ion sources mounted to a support plate defining the sixteen beam array. The beamlets are electrostatically accelerated through a series of electrodes inside an evacuated (10-7 torr) high voltage (HV) accelerating column. The column consists of two 28-inch diameter insulator modules made of 85 percent A1203 ceramic rings brazed to niobium feedthrough rings to which the electrodes are mechanically attached. Field shaping is used to minimize electron avalanche induced flashover along the inside surface of the ceramic rings. The column is self-supporting and is cantilevered from one end of the containment vessel. A brazed assembly was chosen to provide the required bond strength and high vacuum capability. The HV pulsed power supply is a 2MV Marx generator cantilevered from the opposite end of the containment vessel. The stainless steel pressure vessel (PV) contains a 65 psig mixture of SF6(30%) and nitrogen (70%) to provide the electrical insulation.

4 citations


Proceedings ArticleDOI
21 May 1985
TL;DR: The Large Aperture Module (LAM) as discussed by the authors is the final amplifier of the Los Alamos Aurora krypton fluoride (KrF) laser system, which consists of a laser chamber with a 1-× 1m aperture and a 2-m active length which is directly pumped by opposing 1- × 2m electron beams.
Abstract: The large aperture module (LAM) is the final amplifier of the Los Alamos Aurora krypton fluoride (KrF) laser system.1 Ah artist’s conception of the device is shown in Fig. 1. It consists of a laser chamber with a 1-× 1-m aperture and a 2-m active length which is directly pumped by opposing 1- × 2-m electron beams (up to 675 kV at 20 A/cm2). Each electron gun is driven by two 2.7-Ω water pulse forming lines (PFLs) connected in parallel. The PFLs are each 10.7 m long giving a 650-nsec pump pulse. Each pair of water lines is pulse charged by a Marx generator capable of producing up to 1.8 MV. A pair of Helmholz coils is provided to prevent beam pinching in the diodes and to ensure uniform pumping in the laser gas volume. The laser chamber can be filled with up to 1.5 atm of an Ar/ Kr/F2 lasing mixture.

3 citations


ReportDOI
01 Feb 1985
TL;DR: In this article, the authors described the arrangement of the Injector System (made up of an existing High Voltage Marx Generator, a new Four-beam Source array and a Beam Conditioning Unit for matching and steering) and the Accelerator Apparatus which contains the 24 shaped-pulsed accelerating units.
Abstract: The technical description treats the arrangement of the Injector System (made up of an existing High Voltage Marx Generator, a new Four-beam Source array and a Beam Conditioning Unit for matching and steering) and the Accelerator Apparatus which contains the 24 shaped-pulsed accelerating units Flexibility in diagnostic capability and physics experiments has been maintained insofar as possible

2 citations


01 Jan 1985
TL;DR: PBFA-II as discussed by the authors is the second thirty-six module particle beam accelerator built by Sandia for ICF fusion feasibility studies, which is designed to deliver 2.8 terawatts to a central experimental chamber.
Abstract: PBFA-II is the second thirty-six module particle beam accelerator built by Sandia for ICF fusion feasibility studies. Each module of the machine is designed to deliver 2.8 terawatts to a central experimental chamber. The total power delivered (100 terawatts) is expected to permit ignition scaling studies beginning in 1986. The PBFA-II energy storage system consists of thirty-six 6.0 MV, 400 kJ Marx generators set in an annular oil tank at the outer periphery of the accelerator. In order to properly drive the machine's downline pulse-forming section and the accelerator load, the Marx generator set must erect with a first-to-last spread of less than 40 nsec. The energy storage section is triggered by a chain of pulse amplifiers, beginning with a low voltage trigger pulse from the main control system and culminating in thirty-six 540 kV, 80 nsec risetime pulses delivered to the individual Marx generators. Each generator then erects in a 110 kA, 5.3 MV, 1.0 ..mu..sec risetime pulse to charge the pulse-forming section. At this time, the entire energy storage section has been assembled and initial testing has begun on the charging, firing, and arming systems. Performance characteristics, as well as an operating point and procedure, are being determinedmore » for each of the support systems, in preparation for upcoming tests of the Marx generators.« less

1 citations


01 Jan 1985
TL;DR: In this article, the results of measurements of energy transport efficiencies through the successive pulse compression stages of the Particle Beam Fusion Accelerator (PBFA) II were compared with computer circuit code simulations of the hardware design.
Abstract: The 36-module Particle Beam Fusion Accelerator (PBFA II) is designed to provide a 30 MV pulse, with greater than 150 TW, to a centrally located lithium ion diode. Each module is driven by a 6 MV, 400 kJ Marx generator and uses three water-insulated and switched pulse compression stages followed by a voltage inversion-adder unit. All impedance matching transmission-line transformer couples the output pulse from the inversion-adder unit to the central vacuum insulator, plasma erosion switches, and ion diode. The prototype of a single PBFA-II module, called Demon, is being used to test component design, including a mock-up of a section of the vacuum insulator, and to determine overall module operatting characteristics. This paper presents the results of measurements of energy transport efficiencies through the successive pulse compression stages. Results of energy transport measurements on an 18 module, one-fifth scale model, are also compared to the single-line data. We present a comparison of measured parameters with computer circuit code simulations of the hardware design. Comparisons are used to suggest areas of possible improvements. The measured module output characteristics agree with the code simulations and meet the design requirements for the PBFA-II accelerator.

1 citations


Journal ArticleDOI
TL;DR: In this paper, a new type of SF6 spark gap switch was developed for the Marx generator, which was successfully tested as an insulator of the generator for the first case.
Abstract: Technological troubles and new approaches in a pulse-power machine : LIMAYI as a relativistic electron and light ion beam generator are reported. Liquid Fron-113 is successfully tested as insulator of the Marx generator for the first case. We develop a new type of a SF6 spark gap switch for the Marx generator.