A5036318557- Particle accelerators and beam dynamics
- Particle Accelerators and Free-Electron Lasers
- Gyrotron and Vacuum Electronics Research
- Pulsed Power Technology Applications
- Laser-Plasma Interactions and Diagnostics
- High voltage insulation and dielectric phenomena
- Electrostatic Discharge in Electronics
- Plasma Diagnostics and Applications
- Nuclear Physics and Applications
- Particle Detector Development and Performance
- Radiation Detection and Scintillator Technologies
- Magnetic confinement fusion research
- Superconducting Materials and Applications
- Vacuum and Plasma Arcs
- Power Transformer Diagnostics and Insulation
- Electromagnetic Launch and Propulsion Technology
- Integrated Circuits and Semiconductor Failure Analysis
- Thermal Analysis in Power Transmission
- Advanced X-ray Imaging Techniques
- Radiation Effects and Dosimetry
- X-ray Spectroscopy and Fluorescence Analysis
- Ion-surface interactions and analysis
- Microwave Engineering and Waveguides
- Silicon Carbide Semiconductor Technologies
- Ionosphere and magnetosphere dynamics
Pfizer (United States)
2008-2024
Lawrence Livermore National Laboratory
2007-2023
United States Department of Energy
2015
Lawrence Livermore National Security
1999-2007
Lawrence Berkeley National Laboratory
1989-1994
Stanford University
1989
SLAC National Accelerator Laboratory
1989
We have used relativistic klystron technology to extract 290 MW of peak power at 11.4 GHz from an induction linac beam, and a short 11.4-GHz high-gradient accelerator. measured rf phase stability, field emission, the momentum spectrum accelerated electron beam. An average accelerating gradient 84 MV/m has been achieved with 80 power.
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 acceleration of an electron beam. Beam pulse lengths for these experiments were varied from 0.5 /spl mu/s 1.2 full-width half-maximum. A low-frequency inductance-capacitance (LC) oscillation diode voltage current resulted in beam position through interaction with accidental (static) magnetic dipole region. There was no growth amplitude this after propagating...
In heavy-ion inertial-confinement fusion systems, intense beams of ions must be transported from the exit final-focus magnet system through chamber to hit spots on target with radii about 2 mm. For heavy-ion-fusion power-plant scenarios presently favored in U.S., a substantial fraction ion-beam space charge neutralized during this final transport. The most effective neutralization technique found numerical simulations is pass each beam low-density plasma after focusing. To provide...
This work describes the process development and manufacture of early-stage clinical supplies a hepatoselective glucokinase activator, potential therapy for type 2 diabetes mellitus. Critical issues centered on challenges associated with synthesis intermediates API bearing particularly racemization-prone α-aryl carboxylate functionality. In particular, T3P-mediated amidation was optimized coupling acid substrate relatively non-nucleophilic amine. Furthermore, an unusually...
A design for an $X$-band rf photoinjector that was developed jointly by SLAC National Accelerator Laboratory (SLAC) and Lawrence Livermore (LLNL) is presented. The based around a 5.59 cell gun has state-of-the-art features including: elliptical contoured irises; improved mode separation; optimized initial half length; racetrack input coupler; coupling balances pulsed heating with cavity fill time. Radio-frequency beam dynamics modeling have been done using combination of codes including...
The second axis of the Dual Axis Radiographic HydroTest (DARHT) facility will provide up to four short (< 150 ns) radiation pulses for flash radiography high-explosive driven implosion experiments. To accomplish this DARHT-II linear induction accelerator (LIA) produce a 2-kA electron beam with 18-MeV kinetic energy, constant within /spl plusmn/ 0.5% 2-/spl mu/s. A fast kicker cleave out mu/s flattop, bulk diverted into dump. then be transported final-focus magnet, and focused onto tantalum...
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. 24-m long prototype source, RTA, will be constructed in this physics, engineering, and cost issues related RK-TBAs. The RTA generate 200-ns 180-MW (11.4-GHz) pulses from each of eight output ports. major components include a 2.8-MeV 1.2-kA induction injector, transverse beam modulator, adiabatic...
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 (RK-TBA), the drive beam passes through number of output structures. High conversion efficiency electron energy to is achieved in this concept by reacceleration modulated between We have conducted experiments studying extracted from various RK...
Vacuum insulators are critical components in many pulsed power systems. The separate the vacuum and non-vacuum regions, often under great stress due to high electric fields. will flashover at dielectric interface for field values much lower than bulk breakdown through material. Better predictive models computational tools needed enable insulator designs a timely inexpensive manner advanced In this article we discuss physics that have been implemented PIC code better understand initiation of...
Preliminary studies of beam dynamics in a relativistic klystron were done to support design study for 1 TeV two-beam accelerator (RK-TBA), 11.424 GHz microwave power source. This paper updates those studies. An induction is modulated, accelerated 10 MeV, and injected into the RK with RF current about 1.2 kA. The main portion 300-m long extraction section comprised 150 traveling wave output structures 900 cells. A periodic system permanent quadrupole magnets used focusing. One two dimensional...
Experimental work is underway to investigate the feasibility of using relativistic klystrons as a power source for future high-gradient accelerators. The aim develop high-power (500-MW) short-wavelength (2.6-cm) klystron with beam kinetic energy greater than 1 MeV. Two different configurations have been built and tested: high-gain multicavity at 11.4 GHz low-gain two-cavity subharmonic buncher driven 5.7 GHz. In both extracted order understand basic physics issues involved in extracting RF...
The vacuum/dielectric interface of insulators is often the weakest part in high voltage and pulsed power systems. Surface flashover can occur for electric field values much lower than that bulk breakdown through material. Although empirical data many theories be found literature, there are no models used to optimally design reliably predict when will occur. In this presentation we discuss results a FDTD-PIC code being model physics phenomena common theories. order simulate initiation vacuum...
Recent high-voltage breakdown experiments of periodic metallic-dielectric insulating structures have suggested several interesting high-gradient applications. One such area is the employment insulators in high-current, electron-beam, accelerating induction modules. For this application, understanding RF characteristics insulator plays an important role estimating beam-cavity interactions. In paper, we examine properties comparing simulation results with experiment. Different designs are...
When completed, the DARHT-II linear induction accelerator (LIA) will produce a 2 kA, 18 MeV electron beam with more than 1500 ns current/energy "flat-top." In initial tests has already accelerated beams current pulse lengths from 500 to 1200 full-width at half maximum (FWHM) 1.2 kA peak and 12.5 energy. Experiments soon begin ∼ 1600 flat-top pulse, but reduced These are all significantly longer any other multi-MeV LIA, they define novel regime for high-current dynamics, especially regard...
The surface of an insulator under vacuum and electrical charge will flashover when illuminated by a critical dose ultra-violet (UV) radiation - depending on the size material, cone angle, applied voltage shot-history. A testbed comprised excimer laser (KrF, 248 nm, ~16 MW, 30 ns FWHM,), chamber, negative polarity dc high power supply (? -60 kV) were assembled to test 1.0 cm thick angled insulators for surface-flashover. Several candidate materials, e.g. High Density Polyethylene (HDPE),...