Kirkpatrick-Baez Microscope for Hard X-Ray Imaging of Fast Ignition Experiments

Abstract

Fast ignition (FI) decouples the compression and ignition in normal Inertial Confinement Fusion schemes, and can rely on hot electron transport to ignite the compressed core. In order to study electron transport, characteristic K-alpha X-ray emission from copper tracer layers is often employed. A Kirkpatrick-Baez X-ray microscope was constructed using grazing incidence platinum mirrors and characterized to image Cu K-alpha emission in high intensity Fast Ignition experiments. The broad spectral window from 4 to 9 keV enables imaging of both the copper K-alpha emission as well as the emitted Bremsstrahlung radiation from the high intensity interaction spot. A resolution of 30 um or less over a 300 um field of view has been confirmed experimentally. Results from cone-wire experiments are presented where the emission from the high intensity interaction spot and the copper K-alpha emission from the copper wire tip were analysed as a function of prepulse energy.