Showing papers on "Marx generator published in 1993"

Microsecond pulse width, intense, light‐ion beam accelerator

Abstract: A relatively long‐pulse width (0.1–1 μs) intense ion beam accelerator has been built for materials processing applications. An applied Br, magnetically insulated extraction ion diode with dielectric flashover ion source is installed directly onto the output of a 1.2 MV, 300‐kJ Marx generator. The diode is designed with the aid of multidimensional particle‐in‐cell simulations. Initial operation of the accelerator at 0.4 MV indicates satisfactory performance without the need for additional pulse shaping. The effect of a plasma opening switch on diode behavior is considered.

High-speed circuits for TE discharge lasers and high-voltage applications

Abstract: Pulsed transverse electric (TE) glow discharges used to produce population inversions in gas lasers at 1–20 atm require high‐speed, high‐voltage, high‐current capacitor banks. In this article we first review and compare the circuits in common use to produce the required fast, self‐sustained glow discharges in CO2, excimer, and N2 lasers. The parameters and circuit types given will be useful to future designers of pulsed gas lasers to design and to optimize any proposed circuit in order to yield any desired operating conditions and parameters. The n‐stage circuit types presented are capacitor‐transfer (C‐C), L‐C inversion, Marx bank, and fourfold L‐C inversion, with their double‐sided counterparts, and also their transmission‐line counterparts, such as the Blumlein circuit. A one‐parameter differential equation is developed which describes the general series C‐L‐R circuit. Electrical pulses measured on various lasers are compared with the differential equation solutions for various bank impedances and load...

Results of initial testing of the four stage RHEPP accelerator

Abstract: The low power checkout of the Repetitive High Energy Pulsed Power (RHEPP) pulse forming line (PFL) and linear induction voltage adder (LIVA) is complete The accelerator has four LIVA cavities driven via coaxial cables from the PFL that utilizes magnetic switching to provide a 250-kV, 60-ns output pulse The PFL is repetitively charged by a ten stage Marx generator to operate from single shot to five Hz Results from these tests of the initial four stage RHEPP accelerator are presented and compared with design simulations Data from a resistive cavity load and from preliminary electron diode experiments are included While core temperatures remain low during five Hz operation, they are monitored and compared to extrapolated predictions from the design modeling Performance of the Metglas magnetic switches and blocking cores, the voltage addition in the four LIVA cavities, and system efficiencies are discussed Sources of discrepancies from the original design models are identified, and improved models that account for the discrepancies are presented Improved performance potential based on these models is discussed Plans for future testing of the 1-MV system up to 120 kW at 120 Hz and for the full system with ten LIVA cavities are presented

Applying the Marx band circuit configuration to power MOSFET

Abstract: Power MOSFETs operated in a Marx bank circuit configuration are presented. This circuit is useful for generating high voltage (greater than 1 kV) nanosecond risetime pulses. After the design procedure is given an example circuit is designed which generates a -1800 V pulse with a 3-0 ns falltime into 50 Ω

Disk-cathode flash X-ray tube driven by a repetitive two-stage Marx pulser

Abstract: Fundamental studies of a repetitive flash X-ray generator using a diskcathode radiation tube are described. The high-voltage pulser employed a modified two-stage surge-Marx circuit. The two condensers in the pulser were charged from 40 to 60 kV, and the electric charges were discharged to the X-ray tube repetitively to generate flash X-rays. The total capacity during the main discharge was 425 pF, and the maximum output voltage from the pulser was about 1·9 times the charged voltage. The flash X-ray tube of the demountable-diode type and was composed of a rodshaped anode tip made of tungsten, a disk cathode made of graphite and a tube body made of polymethylmethacrylate. The peak tube voltage was primarily determined by the anode-cathode (A-C) space, and the peak tube current was less than 0·5 kA. Thus the maximum photon energy could be easily controlled by varying the A-C space, and the tube current roughly increased according to increases in the charged voltage. The pulse width ranged from 40 to 100 ns, and the X-ray intensity was less than 1·1 μC kg−1 at 0·5 m per pulse. The repetition rate was less than 50 Hz, and the effective focal spot size was equivalent to the anode diameter.

High Power Repetitive Stacked Blumlein Pulse Generators Producing Waveforms with Pulse Durations Exceeding 500 N Sec

Abstract: : The repetitive stacked Blumlein pulse power generators developed at the University of Texas at Dallas (UTD) consist of several triaxial Blumleins stacked in series at one end. The lines are charged in parallel and synchronously commuted with a single thyratron at the other end. The number of lines can be varied from 2 to 12 and in this way, relatively low charging voltages are multiplied to give a high discharge voltage across an arbitrary load without the need for Marx bank circuitry. In this report, performances of these Blumlein pulsers with different line configurations and extended line lengths are given. It is demonstrated that they are capable of producing switching waveforms with fast risetimes and with pulse durations exceeding 500 nsec without degradation of the voltage gains. The existing opportunities in tactically packaging these devices are discussed and demonstrated.

Deoxidization of Carbon Dioxide by Pulse Power Discharge

Abstract: Carbon dioxide was effectively reduced to carbon monoxide by pulse power discharge. Linear discharge in a glass tube filled with CO2 or CO2 and H2 gas mixture at 150 to 450 Torr pressure was powered by a low-impedance Marx generator (about 3 Ω, 200 kVmax, stored energy, 10 kJ). The maximum reduction efficiency was 290 nmol/sW (the electric power used in the estimation was the stored energy in capacitors of the Marx generator).

Integrated Marx generator

Abstract: An integrated Marx generator circuit is constructed in one assembly from a housing with two oil-filled cavities. First and second capacitors each include two sets of spaced apart capacitor plates. The first and second capacitors are formed in the separate cavities. The space between the capacitor plates are filled with oil and insulating material. A set of four spark gap switches control the charging and discharging of the generator circuit.

SYSTEM OF 500 kV MARX GENERATOR FOR LIA-10 RADIAL LINES CHARGING

Abstract: In -0.g j is time the radial lines of 48 cavities in thc lincar induction accclcrator LIA-10 arc chargcd up to 400500 kV with 16 five-stage one-circuit Marx generator. Thc gcncrator clcctric schcmc is prcscntcd as wcll as somc of its design peculiarities, the arrangement and characteristics of gas-filled trigatrotis in the stages. Stored energy is 6.25 kJ. cquivalcnt capacitancc is 0.05 pF. output voltagc is -500 kV, circuit inductance is -2.5 jiHs At -100 % electrical strength rcscrvc for thc switchcs and with synchronizcd triggering of all generators the maximum jitter is +I5 ns for -lo4 shots. During 15 years the generators set has operated successfully in LIA-10. In lincar induction accclcrator LIA10 [ 1) thc accelerating system comprises 16 accelerator units with 96 radial watcr-insulatcd lincs for accelerating voltagc pulsc formation. In -0.8 ps time the capacitances of 6 radial lines of each unit are charged up to 400-500 kV by Marx generators (Ma), thrcc cavitys by its own gcncrators. which constitute a pulse charging setup of 16 MWs in total. Basic requirement to this sctup high rcliability and synchronous operation of all MWs at high reserve of electric strength in a series of 5 ~ 1 0 ~ joint switchings. So. thc clcctric schcmc and dcsign of a singlc MG wcrc claboratcd at first, and thc subsequent assembling of all M a ' s was done of single-type tcstcd units an componcnts that has simplified thc systcm fabrication, adjustment and operation. In Fig.1 thc clcctrical schcmc of a fivc-stagc MG is presented. As energy storage C for cach stage onc capacitor 0.25 pF 100 kV is uscd, Commutators S1-S5 arc identical trigatron controlled with a field disturbance technique. The SI electrodes conncctions with thc first stagc componcnts diffcr from thc ones in the second and the third stages, which connectors diffcr in thcir turn from thc oncs in thc fourth and thc fifth stages. Thc voltagc pulsc Ut of thc positivc polarity trigger SI being applied via capacitor C, 250 pF and resistor R, = 51 R . Thc subscqucnt trigatron S2-S5 opcration in is initiated with pulsed potential differences appeared between its clcctrodcs at thc trigatron brcakdown in thc prcvious stagc. Thc intcr-clcctrodc switch capacitanccs in thc stagc C 1= 110 pF, C2-50 pF, C3-15 pF, C4=13 pF. CS-10 pF play an important rolc; thcy arc shown only as an cxamplc in the second stage. After SI breakdown the potential of the main clcctrodc E l in 52 dccrcasc rapidly from +U up to zcro duc to C4 dischargc via R4=300 R and SI. rcsulting in the probable pulsed potential difference of U magnituds bctwccn thc control clcctrodc EC and El , and bctwccn EC and the second main electrode E2 it may constitute -1.7U. A s thc EC potcntial is positivc in rcgard to thc both main 4 C

A microsecond-pulsewidth, intense, light-ion beam accelerator

Abstract: A relatively long-pulsewidth (0.1 - 1.0 μs) intense ion beam accelerator has been built for materials processing applications. An applied-Br, magnetically-insulated extraction ion diode with dielectric flashover ion source is installed directly onto the output of a 1.2-MV, 300-kJ Marx generator. Initial operation of the accelerator at 0.4 MV indicates satisfactory performance without the need for additional pulse-shaping.

Retrofit Conversion of a Low Impedance, Short Pulse Electron Beam Accelerator to High Impedance, Long Pulse Operation

Abstract: : An existing relativistic electron beam generator has been modified to increase its output pulse width from 100 ns to either 300 ns or 1,000 ns. In its original form, the generator consisted of a water insulated, 5.25 omega coaxial pulse forming line (PFL) that discharged into a field emission diode through a low inductance gas-pressurized spark gap switch. A twenty stage Marx generator charged to the PFL to as high as 2 MV. At this voltage, an 1 MV output pulse is developed into a matched load. An adjustable resistor shunting the PFL permitted matching its output to load impedances higher than 5.25 omega.