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ABSTRACT: A fully integrated test facility for the National Ignition Facility (NIF) Power Conditioning System (PCS) was completed in August of 2000 at LLNL. The system consists of the computer control and data acquisition subsystem, a 24kV 2.2-MJ Main Energy Storage Module (MESM), twenty 180ft lengths of high voltage transmission cable, and a standard NIF flashlamp, load (the Frame Assembly Unit or FAU). The MESM can contain up to 24 (20 nominal) 300uF energy storage capacitors. Stainless steel inductive/resistive (9uh/0.026 ohms) damping elements limit fault currents in the event of a capacitor or main bus failure. A single spark-gap switches the entire bank output through ballast inductors to the output cables. Each cable has it own ballast inductor to insure current sharing, the values of the inductors are varied with cable length. The test facility can be fired once every ten minutes with a total peak output current of 580kA at pulse width of 400μs. We will present in detail tests performed to demonstrate that the system meets all specifications for operational performance well as statistical data verifying stability and reliability.
Pulsed Power Plasma Science, 2001. PPPS-2001. Digest of Technical Papers; 02/2001
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ABSTRACT: Designing and developing the 1.7- to 2.1-MJ power conditioning
system (PCS) that power the flashlamps of the main and power amplifiers
for the National Ignition Facility (NIF) lasers is one of several
responsibilities assumed by Sandia National Laboratories (SNL) and
Maxwell Physics International in support of the NIF Project. The NIF is
currently being constructed at Lawrence Livermore National Laboratories
(LLNL). The test facility that evolved over three years to satisfy the
project requirements is called the First Article NIF Test Module
(FANTM). It was built at SNL and operated for about 17000 shots to
demonstrate component performance expectations over the lifetime of NIF.
A few modules are used initially in the amplifier test phase of the
project. The final NIF system requires at least 192 modules in the four
capacitor bays. The paper briefly summarizes the final design of the
FANTM facility and compares its performance with the predictions of
circuit simulations for both normal operation and fault-mode response.
Applying both the measured and modeled power pulse waveforms as input to
a LLNL amplifier gain code indicates that the 20-capacitor PCS can
satisfy the NIF requirement for an average gain coefficient of 5.00%/cm
and can exceed 5.20%/cm with 24 capacitors
IEEE Transactions on Plasma Science 11/2000; · 1.17 Impact Factor
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ABSTRACT: The laser glass for the National Ignition Facility (NIF) main amplifier system is pumped by a system of 192 pulsed power/flash lamp assemblies. Each of these 192 assemblies consists of a 1.6 MJ (nominal) capacitor bank working with a pre-ionization/lamp check (PILC) pulser to drive an array of 40 flash lamps. This paper describes the predicted performance of these power conditioning system (PCS) modules in concert with flashlamp assemblies in NIF. Each flashlamp assembly consists of 20 parallel sets of lamps in series pairs. The sensitivity of system performance to various design parameters of the PILC pulser and the main capacitor bank is described. Results of circuit models are compared to sub-scale flashlamp tests and to measurements taken in tests of a PCS module driving a flashlamp assembly in the First Article NIF Test Module facility at Sandia National Laboratories. Also included are predictions from a physics-based, semi-empirical amplifier gain code.
Pulsed Power Conference, 1999. Digest of Technical Papers. 12th IEEE International; 02/1999
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ABSTRACT: Designing and developing the 1.7 to 2.1-MJ power conditioning system (PCS) that powers the flashlamps for the National Ignition Facility (NIF), currently being constructed at Lawrence Livermore National Labs (LLNL), is one of several responsibilities assumed by Sandia National Labs (SNL) in support of the NIF Project. The test facility that has evolved over the last three years to satisfy the project requirements is called FANTM. It was built at SNL and has operated for about 17,000 shots to demonstrate component performance expectations over the lifetime of NIF. The final full NIF system will require 192 PCSs (48 in each of four bays). This paper briefly summarizes the final design of the FANTM facility and compares its performance with the predictions of circuit simulations for both normal operation and fault-mode response. A physics-based, semi-empirical amplifier gain code indicates that the 20 capacitor PCS can satisfy the NIF requirement for an average gain coefficient of 5.00 %/cm and can exceed 5.20 %/cm with 24 capacitors.
Pulsed Power Conference, 1999. Digest of Technical Papers. 12th IEEE International; 02/1999
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ABSTRACT: Summary form only given, as follows. Plasma opening switch (POS)
experiments have been performed on the PBFA II to develop a switch which
will provide voltage and power gain to an applied- B lithium ion
diode. These experiments have successfully coupled power to electron and
ion beam diodes using a magnetically-injected-plasma (MIP) POS. Carbon
plasma with electron densities of 1×10<sup>12</sup> to 2×10
<sup>13</sup>/cm<sup>3</sup> has been injected from the anode into the
8-cm gap of the 20-Ω magnetically insulated transmission line
(MITL) of PBFA II along a B <sub>r.z</sub> magnetic field. The
MIP switch uses the inertia of the plasma to keep the switch closed and
the magnetic pressure of B <sub>0</sub> from the conduction
current to open the switch. The configuration of the injecting magnetic
field and the plasma source, has a significant effect on the efficiency
of coupling power to high-impedance loads. Plasma near the center of the
injecting magnetic field limits the opening impedance of the switch and
subsequently the power delivered to the load. The axial location of the
switch with respect to the load has also been identified as a critical
parameter in increasing the coupling efficiency. A length of 10 to 20 cm
of MITL between the POS and the load has increased the power delivered
to the load
Plasma Science, 1990. IEEE Conference Record - Abstracts., 1990 IEEE International Conference on; 06/1990
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ABSTRACT: Summary form only. The authors have developed and tested three different plasma-opening switch (POS) designs that use magnetic fields to control and confine the injected plasma. All three configurations couple current efficiently to a 5-Ω electron beam diode. In the first switch, a plasma generated by flashboard sources is injected into the 20-Ω magnetically insulated transmission line through six equally spaced 30°-wide azimuthal segments. The magnetic field from conduction of current through the plasma spoke surrounds and helps to confine the plasma. The second switch uses a magnetically injected plasma (MIP) source. The opening current is determined by the intensity of a preimposed magnetic field at the anode that is used to inject the plasma and hold it in place. The switch opens after the magnetic pressure of the conduction current overcomes the pressure produced by the injecting magnetic field and the inertia of the plasma and pushes a gap open at the cathode. Once the switch opens, the machine current forces the plasma back into the anode. The rate of the current rise is faster (in excess of 2×10<sup>14</sup> A/s) into short-circuit loads than with the segmented POS. The third switch uses the same plasma source as the MIP POS and, to get more efficient coupling, adds a rapidly rising magnetic field at the cathode to increase the force pushing the plasma back into the anode. The current-toggled POS performs as well as the MIP POS when coupled to short-circuit and high-impedance loads. It also allows current to be coupled more efficiently when opening near the peak generator current than it would if only the pre-imposed magnetic field were used at the anode
Plasma Science, 1989. IEEE Conference Record - Abstracts., 1989 IEEE International Conference on; 06/1989
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Pulsed Power Conference, 1989. 7th; 02/1989
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W.A. Stygar,
R.B. Spielman,
H.C. Ives, W.B.S. Moore,
J.F. Seamen,
A.W. Sharpe,
T.C. Wagoner,
T.L. Gilliland,
R.S. Broyles,
J.A. Mills,
T.A. Dinwoodie,
J.S. Slopek,
K.W. Struve,
P.G. Reynolds
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ABSTRACT: New differential D-dot and B-dot monitors were developed for the Z
vacuum section of an accelerator pulsed power supply. The D-dots measure
voltage at the insulator stack. The B-dots measure current at the stack
and in the outer magnetically-insulated transmission lines. Each monitor
has two outputs that allow common-mode noise to be cancelled to the
first order. The differential D-dot has one signal and one noise
channel; the differential B-dot has two signal channels with opposite
polarities. Each of the two B-dot sensors in the differential B-dot
monitor has four 3 mm diameter loops and is encased in copper to reduce
flux penetration. For both types of probes, two 2.2 mm diameter coaxial
cables connect the outputs to a Prodyn balun for common-mode-noise
rejection. The cables provide reasonable bandwidth and generate
acceptable levels of Compton drive in the bremsstrahlung field of the Z
accelerator. A new cavity B-dot is being developed to measure the total
Z current 4.3 cm from the axis of the z-pinch load. All of the sensors
are calibrated with 2-4% accuracy. The monitor signals are reduced with
Barth or Weinschel attenuators, recorded on Tektronix 0.5 ns/sample
digitizing oscilloscopes, and software cable compensated and integrated
Pulsed Power Conference, 1997. Digest of Technical Papers. 1997 11th IEEE International;
