Time-Resolved keV Emission Spectra from Hot, Dense Buried Layer K-Shell and L-Shell Targets.

We report new time-resolved measurements for 50 nm thick Al and Ge buried layer targets. The top-coat thickness of carbon is varied between 0 and 100 nm. A single beam of the Compact Multipulse Terawatt (COMET) laser is frequency doubled, at 527 nm wavelength, up to 1 J energy in a 500 fs (FWHM) pulse and focused to a maximum of 7 x 1017 W cm-2 with an off-axis parabola. An RbAP (001) von Hamos curved crystal spectrometer with an 500 fs x-ray streak camera is fielded to measure the time history of the Al n = 2 - 1 K-shell emission and the Ge n = 3 - 2 L-shell emission in the 7 - 10 Å waveband. The main objective is to generate and study hot, Te ~ 100 - 200 eV, dense, ne ~ 1023 cm-3, thermal plasmas in tamped optically thin targets under a range of laser irradiance conditions. We observe short-lived emission lasting a few picoseconds and indications of cooler, denser plasmas with increasing thickness of the tamping carbon layers. [ABSTRACT FROM AUTHOR]