KHz femtosecond laser-plasma hard x-ray and fast ion source

We describe the first demonstration of a new stable, kHz femtosecond laser-plasma source of hard x-ray continuum and K-alpha emission using a thin liquid metallic jet target. kHz femtosecond x-ray sources will find many applications in time-resolved x-ray diffraction and microscopy studies. As high intensity lasers become more compact and operate at increasingly high repetition-rates, they require a target configuration that is both repeatable from shot-to-shot and is debris-free. We have solved this requirement with the use of a fine (10-30 mum diameter) liquid metal jet target that provides a pristine, unperturbed filament surface at rates > 100 kHz. A number of liquid metal targets are considered. We will show hard x-ray spectra recorded from liquid Ga targets that show the generation of the 9.3 keV and 10.3 keV, K-alpha and K-beta lines Superimposed on a multi-keV Bremsstrahlung continuum, This source was generated by a 50fs duration, 1 kHz, 2W, high intensity Ti:Sapphire laser. We will discuss the extension of this source to higher powers and higher repetition rates, providing harder x-ray emission, with the incorporation of pulse-shaping and other techniques to enhance the x-ray conversion efficiency.