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

The Z-Beamlet laser backlighter system at Sandia National Laboratories, whi ch 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 , 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 t he 2 omega energy in a similar to 50-mum-diam focal spot, the resulting >4 x 10(16) W/cm(2) irradiances will generate greater than or equal to8.950, 8 .999 keV (zinc He-alpha, 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 sig nal-to-noise levels significantly better than presently possible on Z using existing methods. In combination with a similar to1 cm field of view, the technique will be well suited to the large, relatively opaque objects chara cteristic of Z experiments. This addition is anticipated to have a major im pact upon the basic physics of z-pinch implosions, and therefore, possibly the ultimate x-ray powers and hohlraum (vacuum or dynamic) radiation temper atures 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-densi ty physics experiments to be studied at even higher spatial resolution and signal-to-noise levels. (C) 2001 American Institute of Physics.