XUV Aluminum Spectra of Laser-Produced Plasmas.

XUV aluminum spectra from 200 to 500 A of laser-produced plasmas are discussed. The plasmas were obtained by focusing Ndglass and CO2 laser pulses onto planar targets. The spectrograph was a normal incidence instrument without an entrance slit. Therefore monochromatic images of the plasma are formed at the focal plane, rather than spectral lines. Kodak 101 film was used to record the spectra. Images of the plasmas due to transitions in Al V through Al X were identified using a theoretical synthetic aluminum spectrum. The time- and space-integrated relative numbers of the ions form Al V through Al X can be obtained from a comparison of the synthetic and laser-plasma spectra. The comparison enables determination of the film calibration curve and the efficiency of the instrument with wavelength. The morphology of the expansion of the plasma is also discussed. The plasma of the highest temperature ions Al X expands outward in cylindrially shaped structures. The expansion of the lower temperature plasma such as Al VII is also cylindrical in appearance, but the images are not as tightly confined to the target normal as for the hotter ions. Author