High-resolution x-ray radiography with Fresnel zone plates on the University of Rochester’s OMEGA Laser Systems

Abstract

Experiments performed at the Laboratory for Laser Energetics with a continuous-wave (cw) x-ray source and on the OMEGA and OMEGA EP Laser Systems [Boehly et al., Opt. Commun. 133, 495 (1997) and Waxer et al., Opt. Photonics News 16, 30 (2005)] have utilized a Fresnel zone plate (FZP) to obtain x-ray images with a spatial resolution as small as ∼1.5 μm. Such FZP images were obtained with a charge-coupled device or a framing camera at energies ranging from 4.5 keV to 6.7 keV using x-ray line emission from both the cw source and high-intensity, laser-beam–illuminated metal foils. In all cases, the resolution test results are determined from patterns and grids backlit by these sources. The resolutions obtained are shown to be due to a combination of the spectral content of the x-ray sources and detector resolution limited by the magnification of the images (14× to 22×). High-speed framing cameras were used to obtain FZP images with frame times as short as ∼30 ps. Double-shell implosions on OMEGA were backlit by laser-irradiated Fe foils, thus obtaining a framing-camera–limited, FZP-image resolution of ∼3 μm–4 μm.

Wire, hybrid, and laser-cut X-pinches as Talbot–Lau backlighters for electron density diagnostics

“…Historically, a variety of x-ray backlighting imaging diagnostics have been employed in HED experiments, including high-resolution monochromatic x-ray imaging systems such as point-projection and pinhole cameras [3,[11][12][13][14], Kirkpatrick-Baez microscopes [15,16], Fresnel zone plates [17,18], and spherically bent crystal systems [19,20]. Typically, these diagnostics measure attenuation, however, when probing low-Z matter with ∼1-100 keV x-rays, the amount that the light is refracted is much more than the amount that is absorbed [21], as seen in figure 1 from [21].…”