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Updated: Jun 27, 2026

Applying X-ray Imaging Crystal Spectroscopy for Use as a High Temperature Plasma Diagnostic
Published on: August 25, 2016
High order reflectivity of highly oriented pyrolytic graphite crystals for x-ray energies up to 22 keV
T Döppner1, P Neumayer, F Girard
1Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551, USA.
Abstract:
We used Kr K alpha (12.6 keV), Zr K alpha (15.7 keV), and Ag K alpha (22.2 keV) x-rays, produced by petawatt-class laser pulses, to measure the integrated crystal reflectivity R(int) of flat highly oriented pyrolytic graphite (HOPG) up to the fifth order. The maximum R(int) was observed in first order (3.7 mrad at 12.6 keV), decreasing by a factor of 3-5 for every successive order, and dropping by a factor of 2-2.5 at 22.2 keV. The current study indicates that HOPG crystals are suitable for measuring scattering signals from high energy x-ray sources (E > or = 20 keV). These energies are required to penetrate through the high density plasma conditions encountered in inertial confinement fusion capsule implosions on the National Ignition Facility.
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