A comparison of past and present computational methods for shape analysis of double-shell x-ray radiographs.

Implosion symmetry is a key requirement in achieving a robust burning plasma in inertial confinement fusion experiments. In double-shell capsule implosions, we are interested in the shape of the inner shell as it pushes on the fuel. Shape analysis is a popular technique for studying said symmetry during implosion.

Invited article: X-ray phase contrast imaging in inertial confinement fusion and high energy density research.

X-ray phase contrast imaging (XPCI) provides enhanced image contrast beyond absorption-based x-ray imaging alone due to refraction and diffraction from gradients in the object material density. It is sensitive to small variations in density, such as internal voids, cracks, grains, defects, and material flow, as well as to stronger density variations such as from a shock wave. Beyond its initial use in biology and materials science, XPCI is now routinely used in inertial confinement fusion (ICF) and high energy density (HED) research, first to characterize ICF capsules and targets, and later applied in dynamic experiments, where coherent x-ray sources, ultrafast x-ray pulses, and high temporal and spatial resolution are required.

Novel fabrication tools for dynamic compression targets with engineered voids using photolithography methods.

Mesoscale imperfections, such as pores and voids, can strongly modify the properties and the mechanical response of materials under extreme conditions. Tracking the material response and microstructure evolution during void collapse is crucial for understanding its performance. In particular, imperfections in the ablator materials, such as voids, can limit the efficiency of the fusion reaction and ultimately hinder ignition.

Multi-frame, ultrafast, x-ray microscope for imaging shockwave dynamics.

Inertial confinement fusion (ICF) holds increasing promise as a potential source of abundant, clean energy, but has been impeded by defects such as micro-voids in the ablator layer of the fuel capsules. It is critical to understand how these micro-voids interact with the laser-driven shock waves that compress the fuel pellet. At the Matter in Extreme Conditions (MEC) instrument at the Linac Coherent Light Source (LCLS), we utilized an x-ray pulse train with ns separation, an x-ray microscope, and an ultrafast x-ray imaging (UXI) detector to image shock wave interactions with micro-voids.

Neural network for 3D inertial confinement fusion shell reconstruction from single radiographs.

In inertial confinement fusion (ICF), x-ray radiography is a critical diagnostic for measuring implosion dynamics, which contain rich three-dimensional (3D) information. Traditional methods for reconstructing 3D volumes from 2D radiographs, such as filtered backprojection, require radiographs from at least two different angles or lines of sight (LOS). In ICF experiments, the space for diagnostics is limited, and cameras that can operate on fast timescales are expensive to implement, limiting the number of projections that can be acquired.

Layered Bi2Se3 nanoplate/polyvinylidene fluoride composite based n-type thermoelectric fabrics.

In this study, we report the fabrication of n-type flexible thermoelectric fabrics using layered Bi2Se3 nanoplate/polyvinylidene fluoride (PVDF) composites as the thermoelectric material. These composites exhibit room temperature Seebeck coefficient and electrical conductivity values of -80 μV K(-1) and 5100 S m(-1), respectively, resulting in a power factor approaching 30 μW m(-1)K(-2). The temperature-dependent thermoelectric properties reveal that the composites exhibit metallic-like electrical conductivity, whereas the thermoelectric power is characterized by a heterogeneous model.

Flexible thermoelectric fabrics based on self-assembled tellurium nanorods with a large power factor.

Highly-flexible thermoelectric fabrics were fabricated based on a layered structure, composed of a thin active layer of self-assembled tellurium nanorods and a substrate layer of polyvinylidene fluoride. The resulting thermoelectric fabrics show a high room temperature power factor of 45.8 μW m(-1) K(-2), which opens a new avenue to fabricate highly-flexible sustainable energy sources.