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High-powered pulsed-ion-beam acceleration and transport

Description: The state of research on intense ion beam acceleration and transport is reviewed. The limitations imposed on ion beam transport by space charge effects and methods available for neutralization are summarized. The general problem of ion beam neutralization in regions free of applied electric fields is treated. The physics of acceleration gaps is described. Finally, experiments on multi-stage ion acceleration are summarized.
Date: November 1, 1981
Creator: Humphries, S. Jr. & Lockner, T.R.
Partner: UNT Libraries Government Documents Department

The light ion LMF and its relevance to IFE

Description: The inertial confinement fusion (ICF) program at Sandia National Laboratories (SNL) is directed toward validating light ions as an efficient driver for ICF defense and energy applications. The light ion laboratory microfusion facility (LMF) is envisioned as a facility in which high gain ICF targets could be developed and utilized in defense-related experiments. The relevance of LMF technology to eventual inertial fusion energy (IFE) applications is assessed via a comparison of LMF technologies with those projected in the Light Ion Beam Reactor Assessment (LIBRA) conceptual reactor design study.
Date: December 1, 1993
Creator: Olson, R. E.; Allshouse, G. O.; Cook, D. L.; Lockner, T. R.; Mazarakis, M. G.; Olson, C. L. et al.
Partner: UNT Libraries Government Documents Department

The LMF triaxial MITL voltage adder system

Description: The light-ion microfusion driver design consists of multiple accelerating modules fired in coincidence and sequentially in order to provide the desired ion energy, power pulse shape and energy deposition uniformity on an Inertial Confinement Fusion (ICF) target. The basic energy source is a number of Marx generators which, through the appropriate pulse power conditioning, provide the necessary voltage pulse wave form to the accelerating gaps or feeds of each module. The cavity gaps are inductively isolated, and the voltage addition occurs in the center conductor of the voltage adder which is the positive electrode while the electrons of the sheath flow closer to the outer cylinder which is the magnetically insulated cathode electrode. Each module powers a separate two-stage extraction diode which provides a low divergence ion beam. In order to provide the two separate voltage pulses required by the diode, a triaxial adder system is designed for each module. The voltage addition occurs in two separate MITLs. The center hollow cylinder (anode) of the second MITL also serves as the outer cathode electrode for the extension of the first voltage adder MITL. The voltage of the second stage is about twice that of the first stage. The cavities are connected in series to form the outer cylinder of each module. The accelerating modules are positioned radially in a symmetrical way around the fusion chamber. A preliminary conceptual design of the LMF modules with emphasis on the voltage adders and extension MITLs will be presented and discussed.
Date: December 31, 1992
Creator: Mazarakis, M. G.; Smith, D. L.; Bennett, L. F.; Lockner, T. R.; Olson, R. E. & Poukey, J. W.
Partner: UNT Libraries Government Documents Department

Uniform current density and divergence control in high power extraction ion diodes

Description: A theory of radial beam uniformity in extraction ion diodes is presented. The theory is based on a locally one dimensional analysis of the diamagnetic compression of magnetic streamlines and the self consistent determination of the virtual cathode location. The radial dependence of the applied magnetic field is used to determine the critical parameters of this locally one dimensional treatment. The theory has been incorporated into the ATHETA magnetic field code to allow the rapid evaluation of realistic magnetic field configurations. Comparisons between the theoretical results, simulations with the QUICKSILVER code, and experiments on the PBFA-X accelerator establish the usefulness of this tool for tuning magnetic fields to improve ion beam uniformity. The consequences of poor beam uniformity on the evolution of ion diode instabilities are discussed with supporting evidence from simulations, theory, and experiments.
Date: July 1, 1996
Creator: Desjarlais, M.P.; Coats, R.S.; Lockner, T.R.; Pointon, T.D.; Johnson, D.J.; Slutz, S.A. et al.
Partner: UNT Libraries Government Documents Department

LIF standoff research

Description: Present LIF target experiments on PBFA II use a barrel diode in which the total transport length from the anode to the target is {le} 15 cm. Future LIF development includes high yield applications (LMF) and energy production (ETF and LIBRA power plants) that require standoff - the generation of extracted ion beams and transport of these beams over distances of several meters. Standoff research includes the development of high efficiency extraction diodes (single stage and two-stage), improvements in beam quality (divergence, purity, uniformity, etc.), and the efficient transport and focusing of these beams over distances of several meters to a fusion target. Progress in all of these areas is discussed, as well as a strategy to reduce the divergence from the present 17 mrad for 5 MeV protons on SABRE to the required mrad for 35 MeV Li ions for LMF. The status of experiments is summarized, and future directions are indicated.
Date: September 1, 1994
Creator: Olson, C. L.; Cuneo, M. E.; Desjarlais, M. P.; Filuk, A. B.; Hanson, D. L.; Lockner, T. R. et al.
Partner: UNT Libraries Government Documents Department

Ion beam generation and focusing on PBFA (Particle Beam Fusion Accelerator) II

Description: During the past year we have succeeded in obtaining a 5 TW/cm{sup 2} proton focus on Sandia National Laboratories' Particle Beam Fusion Accelerator (PBFA) II. This has allowed us to shift our experimental emphasis to the implementation of an improved ion diode geometry for higher voltage operation, full azimuthal beam characterization, and especially lithium ion source experiments. We have made significant progress in each of these areas during the past year, demonstrating 10 MV diode operation, {plus minus}10% azimuthal beam symmetry, and promising initial results from lithium ion source experiments. 8 refs., 6 figs.
Date: January 1, 1990
Creator: Stinnett, R.W.; Bailey, J.E.; Bieg, K.W.; Coats, R.S.; Chandler, G.; Derzon, M.S. et al.
Partner: UNT Libraries Government Documents Department

Light ion sources and target results on PBFA II (Particle Beam Fusion Accelerator II)

Description: Advances in ion beam theory, diagnostics, and experiments in the past two years have enabled efficient generation of intense proton beams on PBFA II, and focusing of the beam power to 5.4 TW/cm{sup 2} on a 6-mm-diameter target. Target experiments have been started with the intense proton beams, since the range of protons at 4--5 MeV is equivalent to that of lithium at 30 MeV. Three series of experiments have been conducted using planar, conical, and cylindrical targets. These tests have provided information on ion beam power density, uniformity, and energy deposition. In order to increase the power density substantially for target implosion experiments, we are now concentrating on development of high voltage lithium ion beams. 10 refs., 13 figs.
Date: January 1, 1990
Creator: Cook, D.L.; Bailey, J.E.; Bieg, K.W.; Bloomquist, D.D.; Coats, R.S.; Chandler, G.C. et al.
Partner: UNT Libraries Government Documents Department