Appendix F: Available Target Characterization Techniques

Available Target Characterization Techniques

General Atomics (GA) and LLNL characterization techniques/equipment include the following:

  • Atomic force microscopy: A molecular imaging atomic force microscope system is used to measure target material surfaces with nanometer spatial and height resolution.

  • Confocal microscope 4-pi capsule inspection system: This system allows particles as small as a few microns introduced during assembly to be identified and their location translated to National Ignition Facility (NIF) target chamber coordinates for that specific target.

  • Contact radiography (CR): A nondestructive technique to precisely profile graded dopants in Inertial Confinement Fusion (ICF) shells, this quantitative CR method can detect dopant variation to better than 0.1 at. %. CR also provides accurate dimensional information.

  • Double-sided white-light interferometer: A double-sided white-light interferometer scans both sides of a sample simultaneously to provide thickness measurements over the sample area. Three-dimensional (3D) mapping of ripple and steps in target components to ~1 micron accuracy has been achieved.

  • Dual-confocal measurement system: A dual-confocal measurement system performs thickness measurements over a sample area for opaque samples to complement its x-ray edge absorption spectroscopy unit. 3D mapping of ripples and steps in target components to ~1 micron accuracy has been achieved.

  • Energy dispersive spectroscopy (EDS): A physics-based EDS model examines capsule contaminants and dopants by measuring low concentrations of relatively light elements in a very low-Z matrix.

  • Focused ion beam with scanning electron microscopy: Focused-ion-beam characterization enables site- specific analysis of various capsules

    by conveniently cutting open the thick coating layers and revealing the internal microstructures, defects (if any exist), and composition details.

  • Ion beam characterization: A 4 MV ion accelerator is used to characterize ion implantation doping of ICF ablator capsules with 124Xe atoms and potentially other elements of interest to neutron capture experiments.

  • Micro x-ray computed tomography: An x-ray computed tomography system images materials with a resolution of less than 1 micrometer over a 1-millimeter field of view to provide spatially resolved opacity that can be translated to density in known compositions and thicknesses.

  • Nikon Nexiv optical coordinate measuring machine: This instrument is equipped with custom analysis software for automated mandrel dimensional metrology.

  • Phase shifting diffractive interferometry: The interferometer uses 110 images (medallions) to capture all isolated and gently curved defects on the entire shell surface.

  • Precision radiography: A precision radiography system measures x-ray opacity variation in an ablator capsule to 10–4 accuracy at 120-micron spatial resolution; this includes variations caused by nonuniformity of the dopant layers.

  • Scanning electron microscopy: A scanning electron microscopy with EDS is used for determining capsule dopant profiles and hohlraum microstructure.

  • Transmission electron microscopy with electron energy loss: The transmission electron microscope with electron energy loss spectroscopy capability offers analysis at the atomic structure level and extremely high energy resolution for composition analysis of capsule materials.

  • X-ray edge absorption spectroscopy: An x-ray absorption spectroscopy instrument measures the absorption edge to determine the concentration of elements (Z>17) in the presence of other elements. It can also be used to determine the thickness of opaque samples.

  • X-ray fluorescence (XRF): The XRF system calculates the atomic percentage of elements in spherical samples with an accuracy of 10% for high-Z elements and has a trace detection capability at 1 ppm level for contamination control.

  • X-ray microscopy: A commercial (Xradia) point projection x-ray microscope is used to measure/characterize laser-drilled ll hole geometries to ~1.5-micron resolution.