Investigation of laser-produced high-Z plasma soft X-ray sources

We have investigated laser-produced plasmas (LPP) from high-Z elements as sources of soft X-rays. Emission spectra from several high Z LPPs are observed and the dependence of peak wavelength of unresolved transition array (UTA) emission on atomic number is reviewed. We observed that bismuth (Bi) has strong UTA emission centered at 4 nm, inside of the water window. The effect of laser power density and viewing angle on the spectral emission of Bi LPPs is studied. We also report results on the effect of dual pulse irradiation experiment and emission spectra from a low density Bi foam target.