High-resolution 17–75keV backlighters for high energy density experiments

Abstract

17 – 75 keV one- and two-dimensional high-resolution (<10μm) radiography has been developed using high-intensity short pulse lasers. High energy Kα sources are created by fluorescence from hot electrons interacting in the target material after irradiation by lasers with intensity IL>1017W∕cm2. High-resolution point projection one- and two-dimensional radiography has been achieved using microfoil and microwire targets attached to low-Z substrate materials. The microwire size was 10μm×10μm×300μm on a 300μm×300μm×5μm polystyrene substrate. The radiography experiments were performed using the Titan laser at Lawrence Livermore National Laboratory. The results show that the resolution is dominated by the microwire target size and there is very little degradation from the plasma plume, implying that the high-energy x-ray photons are generated mostly within the microwire volume. There are enough Kα photons created with a 300J, 1-ω, 40ps pulse laser from these small volume targets, and that the signal-to-noise ratio is sufficiently high, for single shot radiography experiments. This unique technique will be used on future high energy density experiments at many new high-power laser facilities.