Generation of x-ray pulses with rapid rise times to pump inner-shell photo-ionized x-ray lasing in carbon at 45 angstrom

An investigation of the rapid rise time of x-ray emission from targets heated by an ultrashort-pulse high-intensity optical laser was conducted for use as a pump for inner-shell photo-ionized x-ray lasing. Results of x-ray rise times from instantaneously heated Au rod targets show little benefit for using optical pulse widths less than 30 fs. Gain calculations for inner-shell photo-ionized lasing show that large gains can be obtained for pulse widths between 30 and 100 fs. Calculated spectra, using the hydrodynamic/atomic kinetics code LASNEX, from a 1 J, 65 fs FWHM pulse optical laser incident on a structured Au target gave a gain of 1 1.5 cm-1 in C at 45 angstrom