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

摘要

17-75 keV one- and two-dimensional high-resolution (< 10 mu m) radiography has been developed using high-intensity short pulse lasers. High energy K alpha sources are created by fluorescence from hot electrons interacting in the target material after irradiation by lasers with intensity I-L > 10(17) W/cm(2). 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 10 mu mx10 mu mx300 mu m on a 300 mu mx300 mu mx5 mu m 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 K alpha photons created with a 300 J, 1-omega, 40 ps 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. (c) 2008 American Institute of Physics.