Spectral content of buried Ag foils at 10{sup 16} W/cm{sup 2} laser illumination

Journal Article · Sat Nov 15 04:00:00 EST 2014 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.4895566· OSTI ID:22303696

Maddox, B. R.; Park, H. -S.; Prisbrey, S.; Remington, B. A. ^[1]

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1. Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

Sources of 5–12 keV thermal Heα x-rays are readily generated by laser irradiation of mid-Z foils at intensities >10{sup 14} W/cm{sup 2}, and are widely used as probes for inertial confinement fusion and high-energy-density experiments. Higher energy 17–50 keV x-ray sources are efficiently produced from “cold” Kα emission using short pulse, petawatt lasers at intensities >10{sup 18} W/cm{sup 2} [H.-S. Park, B. R. Maddox et al., “High-resolution 17–75 keV backlighters for high energy density experiments,” Phys. Plasmas 15(7), 072705 (2008); B. R. Maddox, H. S. Park, B. A. Remington et al., “Absolute measurements of x-ray backlighter sources at energies above 10 keV,” Phys. Plasmas 18(5), 056709 (2011)]. However, when long pulse (>1 ns) lasers are used with Z > 30 elements, the spectrum contains contributions from both K shell transitions and from ionized atomic states. Here we show that by sandwiching a silver foil between layers of high-density carbon, the ratio of Kα:Heα in the x-ray spectrum is significant increased over directly illuminated Ag foils, with narrower lines from K-shell transitions. Additionally, the emission volume is more localized for the sandwiched target, producing a more planar x-ray sheet. This technique may be useful for generating probes requiring spectral purity and a limited spatial extent, for example, in incoherent x-ray Thomson scattering experiments.

• OSTI ID: 22303696
• Journal Information: Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 11 Vol. 85; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CARBON
ENERGY DENSITY
FOILS
INERTIAL CONFINEMENT
K SHELL
KEV RANGE 10-100
LASER RADIATION
LASERS
PETAWATT POWER RANGE
RESOLUTION
SILVER
THOMSON SCATTERING
X RADIATION
X-RAY SOURCES
X-RAY SPECTRA