A5044230381- Particle accelerators and beam dynamics
- Particle Accelerators and Free-Electron Lasers
- Pulsed Power Technology Applications
- Laser-Plasma Interactions and Diagnostics
- Nuclear Physics and Applications
- Plasma Diagnostics and Applications
- Gyrotron and Vacuum Electronics Research
- Medical Imaging Techniques and Applications
- Advanced X-ray and CT Imaging
- X-ray Spectroscopy and Fluorescence Analysis
- Semiconductor Lasers and Optical Devices
- Superconducting Materials and Applications
- Copper Interconnects and Reliability
- Silicon Carbide Semiconductor Technologies
- Advancements in Battery Materials
- Magnetic confinement fusion research
- Psychological Testing and Assessment
- Electromagnetic Launch and Propulsion Technology
- Transport Systems and Technology
- Advanced Data Storage Technologies
- Laser-induced spectroscopy and plasma
- Advanced Aircraft Design and Technologies
- Advanced Battery Technologies Research
- Magnetic Field Sensors Techniques
- Energy Load and Power Forecasting
Lawrence Livermore National Laboratory
2004-2024
Lawrence Livermore National Security
2006
Idaho National Laboratory
1989-2002
Martin Marietta Materials (United States)
1970
The DARHT-II accelerator [1] will produce a 2-kA, 17-MeV beam in 1600-ns pulse when completed this summer. After exiting the accelerator, is sliced into four short pulses by kicker and quadrupole septum then transported for several meters to tantalum target conversion x-rays radiography. We describe tests of kicker, septum, transport, multipulse converter using assembled from first available refurbished cells. This scaled was operated at ~8 MeV ~1 kA, providing with approximately same ?/? as...
We have designed and tested an 87-0 energy dis charge system consisting of two 720-/spl mu/F, 11-kV capacitors discharged through parallel coaxial cables into a 250 nH load. Data will be presented on the current voltage waveforms, with calculated values in ductance resistance. The bank uses solid dielectric switch punctured by explosive bridge wire (EBW) to initiate discharge. With charged 9 kV, 625-kA peak is sent load ringing frequency 6.8 kHz. used transmit are 3 m length. Both RG-217...
Etching of polysilicon features using a helical resonator plasma source is evaluated. Performance metrics consist etching rate, rate uniformity, and profile control HBr/O2–He gas-phase chemistry. The effect power, rf-bias reactor pressure on uniformity examined response surface experiment. Feature determined by examining nested isolated lines trenches oxide mask/polysilicon/oxide structures. Good vertical profiles are obtained at low pressures, high between 50 60 W. operating point for best...
For multi-pulse radiography facilities, we are investigating the possible adverse effects of (1) backstreaming ion emission from bremsstrahlung converter target and (2) interaction resultant plasma with electron beam during subsequent pulses. These would primarily manifest themselves in a static focusing system as rapidly varying X-ray spot. To study these effects, conducting beam-target experiments on ETA-II accelerator (a 6.0 MeV, 2.5 kA, 70 ns FWHM pulsed, accelerator) by measuring spot...
A plastic scintillator has found extensive application in the realm of high-energy physics and national security science. Many applications those fields often involve simultaneous production photons, neutrons, charged particles, which makes relative sensitivity information for these different radiation types important. In this study, we have adopted a multi-head detector comprised high gain phototubes, provides large dynamic range linearity. comparative study on sensitivities scintillators...
An experiment conducted with a megajoule class helical flux compression generator (HFCG), operating into primarily inductive load, is described. The motivation behind the was to benchmark performance of at higher currents and voltages than were tested in prior experiments. intention push operation regime where loss likely become nonlinear, thereby gaining some insight limitations design. Another goal desire suite computational tools used predict design, especially regimes nonlinear loss. In...
As part of the Dual Axis Radiography Hydrotest Facility, Phase II (DARHT II) Multipulse Bremsstrahlung Target effort, we have been performing an investigation (1) possible adverse effects backstreaming ion emission from bremsstrahlung converter target and (2) hydrodynamic behavior after electron beam interaction. Theory predictions show that first effect would primarily be manifested in static focusing system as a rapidly varying X-ray spot. From experiments performed on ETA-II, shown is not...
A family of illumination functions is evaluated. The key property these that they are everywhere infinitely differentiable in the aperture and at edge. Patterns calculated for linear circular apertures, results compared with those given by other functions. Improved performance very low sidelobe designs. Truncated versions considered briefly, encouraging results.
Linear induction accelerators used in X-ray radiography have single-pulse parameters of the order 20 MeV electron beam energy, 2 kA current, pulse lengths 50-100 ns, and spot sizes 1-2 mm. The thermal energy deposited a bremsstrahlung converter target made tantalum from such is /spl sim/80 kJ/cc, more than enough to bring material partially ionized state. tail end single pulse, or any subsequent multi-pulse train, undergoes number interactions with that can affect transport radiographic...
A D-dot voltage probe was designed and tested on a megajoule class flux compression generator (FCG) to measure the load. Design calculations will be shown, along with experimental data taken from laboratory prototype testing as well explosive FCG experiment. The terminated in high impedance amplifier, so that is mostly self-integrating (i.e. capacitive divider). amplifier limits bandwidth of 40 MHz, which sufficient for transients expected sensitivity this termination allows use small,...
Theoretical prediction and particle simulations indicate that an array of longitudinal wires will allow electron beam propagation, without external guiding magnetic field above the drift tube limit, by providing a charge current neutralizing background. This paper presents experimental tests this transport concept injecting 60 ns, 18 kA pulse 1.4 MeV electrons into 1-m long with 1 cm spacing, filling hexagon 8.7-cm average radius. Arrays were tested varying resistances diameters ranging from...
The Mini-G explosive pulsed power system is a two-stage helical-coaxial FCG that geometrically half-scale version of LLNL's FFT device. generator capable delivering 60 MA currents and 10 MJ energy to suitable inductive loads. presently used in high-energy-density physics experiments require efficient current delivery through vacuum flow region the load. As with device, requires compact, high-voltage gas-to-vacuum insulator low-inductance channel achieve high performance maximum delivery. In...
A diagnostic was developed for the determination of temporal history an X-ray spot. pair thin (0.5 mm) slits image x-ray spot to a fast scintillator which is coupled detector, thus sampling slice Two other scintillators/detectors are used determine position and total forward dose. The slit signal normalized dose resulting analyzed get size. information compensate small changes due motion misalignment. time resolution about 5 ns measures spots from 0.5 mm over 3 mm. theory equations calculate...
To successfully tune the DARHT II transport beamline requires close coupling of a model beam and measurement observables as conditions magnet settings are varied. For ETA experiment using components this was achieved SUICIDE (Simple User Interface Connecting to an Integrated Data Environment) data analysis environment FITS (Fully Transport Simulation) model. The has direct access experimental at acquisition predictions for immediate comparison. is coupled into control system where it can...
Gated and streak cameras have been used to look at a high current focused electron beam on target, the X-rays produced by that interaction. An optical camera images transition radiation (OTR) from hitting C target give profiles. Blackbody heavy metal targets is experimentally proven be dominant, The roll bar technique as thick knife edge 'image' X-ray spot beam-target shadow converted visible photons using scintillator imaged gated camera. thickness places limit resolution of diagnostic....
A new type of compact induction accelerator is under development at the Lawrence Livermore National Laboratory that promises to increase average accelerating gradient by least an order magnitude over existing machines. The machine based on use high vacuum insulators, advanced dielectric materials and switches being developed for a variety applications. Research describing extreme variant this technology aimed producing compact, variable output linear proton therapy cancer will be described...