X-ray imaging techniques on Z using the Z-Beamlet laser

Abstract

The Z-Beamlet laser backlighter system at Sandia National Laboratories, which will be operational in 2001, will create a point or area source of high (or moderate) energy x rays behind a Z-accelerator [R. B. Spielman et al., Phys. Plasmas 5, 2105 (1998)] -driven target. In the former case with >2 kJ in up to four pulses of <2 ns total duration in a 20 ns interval, and >80% of the 2ω energy in a ∼50-μm-diam focal spot, the resulting >4 × 1016W/cm2 irradiances will generate ≥8.950, 8.999 keV (zinc He-α, etc.) x rays. This high-energy source, as either a single point or four separate spots, will be used directly for four-frame point-projection x-ray imaging, and will attain spatial resolutions and signal-to-noise levels significantly better than presently possible on Z using existing methods. In combination with a ∼1 cm field of view, the technique will be well suited to the large, relatively opaque objects characteristic of Z experiments. This addition is anticipated to have a major impact upon the basic physics of z-pinch implosions, and therefore, possibly the ultimate x-ray powers and hohlraum (vacuum or dynamic) radiation temperatures that may be attainable. Furthermore, in combination with a slightly defocused point source and a medium-energy grazing-incidence microscope, Z-Beamlet may allow various inertial confinement fusion and high-energy-density physics experiments to be studied at even higher spatial resolution and signal-to-noise levels. © 2001 American Institute of Physics.