Broad M-band multi-keV x-ray emission from plasmas created by short laser pulses

The investigation of the broad M-band x-ray emission from high-Z plasmas created by a laser, with a 30 fs to 3 ps pulse duration and achieving 10(15-17) W/cm(2) on target, is reported. Experimental emission spectra are measured in the energy range from 1.50 to 1.75 keV and discussed as potential backlighting x-ray sources for time-resolved x-ray absorption spectroscopy studies. They are compared with theoretical nonlocal thermodynamic equilibrium calculations of x-ray emission.