A5057743141- Laser-induced spectroscopy and plasma
- Atomic and Molecular Physics
- Magnetic confinement fusion research
- Laser-Plasma Interactions and Diagnostics
- Diamond and Carbon-based Materials Research
- Ionosphere and magnetosphere dynamics
- Plasma Diagnostics and Applications
- Photocathodes and Microchannel Plates
- Nuclear Physics and Applications
- Radiation Detection and Scintillator Technologies
- Particle accelerators and beam dynamics
- Atomic and Subatomic Physics Research
- Copper Interconnects and Reliability
- X-ray Spectroscopy and Fluorescence Analysis
- Metal and Thin Film Mechanics
- Welding Techniques and Residual Stresses
- Laser Design and Applications
- Mass Spectrometry Techniques and Applications
- Radiation Therapy and Dosimetry
- High-pressure geophysics and materials
- Radiation Effects and Dosimetry
- Medical Imaging Techniques and Applications
- Laser Material Processing Techniques
- Advanced X-ray Imaging Techniques
Lawrence Livermore National Laboratory
1995-2025
Johns Hopkins University
1985-1990
We report on record brightness from Ag x-ray emission obtained using a novel laser-produced plasma source. The reported K-shell conversion efficiency of nearly 1% with radiant energy ≈0.6 kJ/sr ions is the highest presently recorded and about twofold greater than more conventional metal-lined cavity targets. He-like are dominant radiators at ≈22.7 keV, which contrast sources other pulse power facilities that produce x-rays Auger processes in near-neutral driven by nonthermal hot electrons...
We report on the performance of high x-ray fluence Kr K-shell sources that are being developed for energy density experiments. These targets 4.1 mm in diameter 4.4 tall hollow epoxy tubes having a 40 μm thick wall holding 1.5 atm gas. For these shots, National Ignition Facility laser delivered nominally constant total ≈750 kJ 351 nm (3ω) light at three power levels [e.g., ≈120 (low), ≈145 (medium), and ≈210 TW (high)]. The (Ephoton = 8–20 keV) radiant intensity (kJ/sr) were found to increase...
Laser heated plasmas have provided recently some of the most powerful and energetic nanosecond length laboratory sources x-ray photons (Ephoton = 1–30 keV). The highest to laser conversion is currently accessible by using underdense (ne ∼ 0.25 nc) since optimal coupling obtained in millimeter scale targets. targets can efficiencies up 10%. Several types be used produce plasmas: metal lined cylindrical cavities, gas pipes, nano-wire foams. Both experimental simulation details these high...
Poloidal rotation velocities in the outer half of ohmically heated Alcator-C plasmas have been determined from Doppler shift impurity emission lines. The measurements were made using a high-resolution photon-counting detector, sensitive to wavelengths \ensuremath{\sim}1200 \ensuremath{\sim}2000 A\r{}, mounted exit plane 1-m Ebert-Fastie spectrometer. following transitions used: 2s2${p}^{1}$P${\ifmmode^\circ\else\textdegree\fi{}}_{1}$--2${p}^{2}$${}^{1}$${D}_{2}$ at 1371.292 A\r{} O v,...
The measured line profiles of the Si iv3s ${\mathrm{}}^{2}$S--3p ${\mathrm{}}^{2}$P\ifmmode^\circ\else\textdegree\fi{} doublet during 10-T operation on Alcator-C tokamak show evidence a contribution due to Zeeman effect these profiles. assumption that are single lines broadened only by instrumental effects and thermal broadening yields apparent kinetic temperatures for two which differ approximately 50%. Neither resulting is reasonable iv under typical Alcator operating conditions difference...
This paper describes the design, construction, and performance of a single-stage microchannel-plate image intensifier used as photon counting detector over wavelength range from 1150 to ∼2000 Å. The intensifer incorporates three high strip current (∼300 μA) microchannel plates, constructed with 12-μ-diam channels 15-μ center–center spacing, in ‘‘Z’’ configuration. use MCPs requires gating power supply protect plates thermal runaway current. output pulses are proximity focused onto P-46...
The poloidal rotation velocity in the edge region of ohmically heated Alcator C plasmas was measured using Doppler shift impurity emission lines. measurements were made a high-resolution, photon counting detector, sensitive to wavelengths from ∼1200 ∼2000 Å, mounted exit plane 1-m Ebert–Fastie spectrometer. transitions used 2s2p 1P01–2p2 1D2 at 1371.292 Å O v and 2s 2S1/2–2p 2P01/2 1242.804 N v, both which exist near limiter radius C. is ∼4.1×105 ±2.1×105 cm/s n̄e∼1.7×1014 cm−3 direction...
A line at 1462.65 A\r{} in the emission spectrum of Alcator-C plasmas seeded with krypton has been identified as 3${s}^{2}$3${p}^{2}$ ${}^{3}$${P}_{0}$--3${s}^{2}$3${p}^{2}$ ${}^{3}$${P}_{1}$ magnetic dipole transition Si-like krypton.
Summary form only given, as follows. We have constructed a 30 diameter plasma source chamber to explore the problems associated with large-area inductively coupled (ICP) sources view towards useful for 400 mm semiconductor wafer processing. Our initial design experiments use 25 planar inductive coil driven at 13.56 MHz. Plasma data is taken in Ar and N/sub 2/ over pressure range 3-50 mTorr powers up 2000 W. Diagnostics include Langmuir probes, B dot optical emission spectroscopy. Electrical...
High fluence K-shell and L-shell x-ray sources are desired for various high energy density physics experiments. One efficient method creating such a source is the laser heating of materials that underdense to light. Nano-wire foams an ideal choice material have average densities 6-15 mg/cm 3 . The manufacture robust Cu, Ag Au nano-wire into millimeter scale targets possible through technique freeze casting aqueous suspension nano-wires. Cylindrical with sizes between 2 4 mm been shot on both...
A photon-counting detector for determination of the ion temperature in magnetically confined plasmas has been developed.1 The is based around an image intensifier tube which fiber optically coupled to a self-scanning linear photodiode array. incorporates three high strip current (∼280 μA) microchannel plates ‘‘Z’’ configuration. Frame times 10 μs are possible through use pixel selection, resulting time resolution on order 5 ms. system will be mounted 1-M Ebert–Fastie spectrometer and used...