Characterization of X-pinch plasma (abstract)

Abstract

The X pinch, in which two or more crossed wires are stretched between the electrodes of the 0.5 TW LION accelerator, is being studied as a bright x-ray source for photopumping an extreme ultraviolet (XUV) laser and for microlithography. Crossed Al or Mg wires with line density from 10 to 400 μg/cm have been imploded by up to 550 kA current for 40 ns. High density and temperature bright spots have been observed at the crossing point. Diagnostics include x-ray pinhole cameras, streak and framing cameras, and XUV x-ray spectrographs. The visible streak camera provides time and radial (or axial) spatially resolved information on the pinch plasma, while the 5 ns single frame camera gives spatially resolved images. The size of the soft x-ray hot spots (less than 40 μm diameter) was estimated from the time-integrated pinhole image. An x-ray spectrograph with a curved mica crystal was used to record K-shell emission spectra. From the line intensity ratios of the K-shell radiation, plasma densities of ∼1020 cm−3 and temperatures about 400 eV were obtained. This work was supported in part by the Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375-5000, under ONR contract N00014-90-J-2002 and NSF grant 89-19960.