Investigation of intense laser-produced hard X-ray sources for radiographic applications

Laser based hard X-ray radiography constitutes a promising tool to investigate matter under high energy density conditions produced in the laboratory. Such hard X-ray sources show short pulse durations, and proper choice of the target geometry (e.g. thin foils and wires) limits the source size to several micrometers. This guarantees a high temporal and spatial resolution that is necessary to investigate hydrodynamically evolving HED matter, while the emitted spectrum of the X-ray source extends far into the 100 keV range, providing enough penetration power to radiograph millimeter size mid-Z targets. Recording high quality radiographic images requires careful characterization and optimization of the source properties. Here, many parameters might play a role, starting from the laser intensity over the target material and geometry to the emission angle regarding the incoming laser beam. We have performed experiments at the PHELIX laser to comprehensively investigate the source properties, using a wide range of laser intensity between 1016 to 1020 W/cm². The emitted spectrum was determined using a set of hard X-ray detectors placed under different angles around the source and foil and wire targets were employed. The results of this experimental campaign will be presented and discussed. Using these results we have performed simulations showing that laser based hard X-ray radiographic imaging of a LAPLAS target – used at the upcoming FAIR facility – will be well suited to retrieve high areal densities. These results will also be presented. Finally, part of a NIF campaign will be presented where X-ray radiography was used to determine mass and density of an imploding plastic sphere, showing very high compression of the plastic.