Author
Timothy L. Houck
Other affiliations: United States Department of Energy
Bio: Timothy L. Houck is an academic researcher from Lawrence Livermore National Laboratory. The author has contributed to research in topics: Particle accelerator & Beam (structure). The author has an hindex of 10, co-authored 60 publications receiving 349 citations. Previous affiliations of Timothy L. Houck include United States Department of Energy.
Papers published on a yearly basis
Papers
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TL;DR: The Virtual National Laboratory for Heavy Ion Fusion (WNLIFI) experiment as discussed by the authors has been used to evaluate the neutralized-transport experiment of heavy-ion inertial-confinement fusion.
Abstract: In heavy-ion inertial-confinement fusion systems, intense beams of ions must be transported from the exit of the final-focus magnet system through the fusion chamber to hit spots on the target with radii of about 2 mm For the heavy-ion-fusion power-plant scenarios presently favored in the US, a substantial fraction of the ion-beam space charge must be neutralized during this final transport The most effective neutralization technique found in numerical simulations is to pass each beam through a low-density plasma after the final focusing To provide quantitative comparisons of these theoretical predictions with experiment, the Virtual National Laboratory for Heavy Ion Fusion has completed the construction and has begun experimentation with the neutralized-transport experiment The experiment consists of three main sections, each with its own physics issues The injector is designed to generate a very high-brightness, space-charge-dominated potassium beam, while still allowing variable perveance by a beam aperturing technique The magnetic-focusing section, consisting of four pulsed quadrupoles, permits the study of magnet tuning, as well as the effects of phase-space dilution due to higher-order nonlinear fields In the final section, the converging ion beam exiting the magnetic section is transported through a drift region with plasma sources for beam neutralization, and the final spot size is measured under various conditions of neutralization In this paper, we discuss the design and characterization of the three sections in detail and present initial results from the experiment
40 citations
18 Apr 2005
TL;DR: The DARHT-II linear-induction accelerator has been successfully operated at 1.2-1.3 kA and 12.5-12.7 MeV to demonstrate the production and acceleration of an electron beam as mentioned in this paper.
Abstract: The DARHT-II linear-induction accelerator has been successfully operated at 1.2-1.3 kA and 12.5-12.7 MeV to demonstrate the production and acceleration of an electron beam. Beam pulse lengths for these experiments were varied from 0.5 /spl mu/s to 1.2 /spl mu/s full-width half-maximum. A low-frequency inductance-capacitance (LC) oscillation of diode voltage and current resulted in an oscillation of the beam position through interaction with an accidental (static) magnetic dipole in the diode region. There was no growth in the amplitude of this oscillation after propagating more than 44 m through the accelerator, and there was no loss of beam current that could be measured. The results of these initial experiments are presented in this paper.
37 citations
TL;DR: In this paper, a test facility is established at Lawrence Berkeley National Laboratory (LBNL) to study RF power sources for linear colliders based on the relativistic klystron two-beam accelerator (RK-TBA) concept.
Abstract: A test facility is established at Lawrence Berkeley National Laboratory (LBNL) to study RF power sources for linear colliders based on the relativistic klystron two-beam accelerator (RK-TBA) concept. A 24-m long prototype source, the RTA, will be constructed in this facility to study physics, engineering, and cost issues related to RK-TBAs. The RTA will generate 200-ns 180-MW RF (11.4-GHz) pulses from each of eight output ports. The major components of the RTA include a 2.8-MeV 1.2-kA induction injector, transverse beam modulator, adiabatic compressor, and RF extraction section. The beam energy is increased to 4 MeV and the RF bunch length is shortened from 240/spl deg/ to 110/spl deg/ in the adiabatic compressor. The 8-m long extraction section includes 40 induction accelerator cells to maintain beam energy at an average 4 MeV, eight equally spaced RF output structures, and a ppm quadrupole focusing system. In this paper, we describe the RTA and present results of component testing and computer simulations.
23 citations
TL;DR: In this paper, a relativistic klystron two-beam accelerator (RK-TBA) was proposed, in which the modulated induction beam current is reaccelerated by passage through subsequent induction accelerator cells.
Abstract: Relativistic klystrons (RK's) are being developed as an RF power source for high gradient accelerator applications which include large linear electron-positron colliders, compact accelerators, and FEL sources. In a relativistic klystron two-beam accelerator (RK-TBA), the drive beam passes through a large number of RF output structures. High conversion efficiency of electron beam energy to RF energy is achieved in this concept by reacceleration of the modulated drive beam between output structures. We have conducted experiments studying the RF power extracted from various RK structures driven by modulated induction accelerator current pulses; our studies include work on improving the transport dynamics of the drive beam. We have started a demonstration in which the modulated induction beam current is reaccelerated by passage through subsequent induction accelerator cells. >
23 citations
12 May 2003
TL;DR: The second axis of the Dual Axis Radiographic HydroTest (DARHT) facility will provide up to four short (< 150 ns) radiation pulses for flash radiography of high-explosive driven implosion experiments as discussed by the authors.
Abstract: The second axis of the Dual Axis Radiographic HydroTest (DARHT) facility will provide up to four short (< 150 ns) radiation pulses for flash radiography of high-explosive driven implosion experiments. To accomplish this the DARHT-II linear induction accelerator (LIA) will produce a 2-kA electron beam with 18-MeV kinetic energy, constant to within /spl plusmn/ 0.5% for 2-/spl mu/s. A fast kicker will cleave four short pulses out of the 2-/spl mu/s flattop, with the bulk of the beam diverted into a dump. The short pulses will then be transported to the final-focus magnet, and focused onto a tantalum target for conversion to bremsstrahlung pulses for radiography. DARHT-II is a collaborative effort between the Los Alamos, Lawrence Livermore, and Lawrence Berkeley National Laboratories of the University of California.
17 citations
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01 Sep 1994
TL;DR: In this article, the authors present a review of Charged Particle Dynamics and Focusing Systems without Space Charge, including Linear Beam Optics with Space Charge and Self-Consistent Theory of Beams.
Abstract: Review of Charged Particle Dynamics. Beam Optics and Focusing Systems Without Space Charge. Linear Beam Optics with Space Charge. Self-Consistent Theory of Beams. Emittance Variation. Beam Physics Research from 1993 to 2007. Appendices. List of Frequently Used Symbols. Bibliography. Index.
1,311 citations
01 Jan 1993
TL;DR: In this article, particle-in-cell (PIC) combined with Monte Carlo collision (MCC) calculations are used for simulation of partially ionized gases, with many of the features met in low-temperature collision plasmas.
Abstract: Many-particle charged-particle plasma simulations using spatial meshes for the electromagnetic field solutions, particle-in-cell (PIC) merged with Monte Carlo collision (MCC) calculations, are coming into wide use for application to partially ionized gases. The author emphasizes the development of PIC computer experiments since the 1950s starting with one-dimensional (1-D) charged-sheet models, the addition of the mesh, and fast direct Poisson equation solvers for 2-D and 3-D. Details are provided for adding the collisions between the charged particles and neutral atoms. The result is many-particle simulations with many of the features met in low-temperature collision plasmas; for example, with applications to plasma-assisted materials processing, but also related to warmer plasmas at the edges of magnetized fusion plasmas. >
1,022 citations
TL;DR: In this article, the state-of-the-art in high-power microwave source research is reviewed, and the history and recent developments of both high-peak power and high-average power sources are reviewed in the context of four main areas of application: (1) plasma resonance heating and current drive; (2) rf acceleration of charged particles; (3) radar and communications systems; and (4) high peak power sources for weapons-effect simulation and exploratory development.
Abstract: This article reviews the state-of-the-art in high-power microwave source research. It begins with a discussion of the concepts involved in coherent microwave generation. The main varieties of microwave tubes are classified into three groups, according to the fundamental radiation mechanism involved: Cherenkov, transition, or bremsstrahlung radiation. This is followed by a brief discussion of some of the technical fundamentals of high-power microwave sources, including power supplies and electron guns. Finally, the history and recent developments of both high-peak power and high-average power sources are reviewed in the context of four main areas of application: (1) plasma resonance heating and current drive; (2) rf acceleration of charged particles; (3) radar and communications systems; and (4) high-peak power sources for weapons-effect simulation and exploratory development.
374 citations
TL;DR: In this paper, high energy electromagnetic processes in Condensed Media have been studied in the context of high energy electromagnetic processes in the nuclear power plant. But they are not considered in this paper.
Abstract: (1973). High-Energy Electromagnetic Processes in Condensed Media. Nuclear Technology: Vol. 18, No. 3, pp. 312-313.
277 citations
TL;DR: Longitudinal compression of a velocity-tailored, intense neutralized beam at 300 keV, 25 mA has been demonstrated and has been confirmed independently with two different diagnostic systems.
Abstract: Longitudinal compression of a velocity-tailored, intense neutralized K{sup +} beam at 300 keV, 25 mA has been demonstrated. The compression takes place in a 1-2 m drift section filled with plasma to provide space-charge neutralization. An induction cell produces a head-to-tail velocity ramp that longitudinally compresses the neutralized beam, enhancing the beam peak current by a factor of 50 and producing a pulse duration of about 3 ns. This measurement has been confirmed independently with two different diagnostic systems.
138 citations