X-ray radiography of gas-gun impact experiments using an X-pinch

A broadband point-projection X-ray backlighter has been commissioned at First Light Fusion Ltd for radiographing shock driven experiments on a two-stage light gas gun. The X-pinch load consisted of four 7.5 um Tungsten wires driven by 100 kA in ~100 ns rise time. This produced a broadband X-ray source with energies up to 30 keV in a 20 ns pulse with a 200-300 um source size. The imaging setup achieved a spatial resolution of 50-100 um in a 30 mm field of view. An elliptically curved LiF crystal spectrometer was used to measure the time-integrated X-ray emission in the energy range 8.4 to 11.3 keV.

The backlighter was used to image density structures within cm-scale length plastic targets driven by a 6 km/s projectile impact. We present radiographs from preliminary experiments along with details of the experimental setup and characterisation of the X-ray source. We demonstrate the ability to image shocks, release waves, projectile deformation and jet density profiles. Results on tungsten L-shell emission will be presented along with plans to perform absorption and/or scattering measurements on both undriven and driven static samples. All these results will be used to inform and validate our in-house modelling capabilities.