Measurements and Simulated Response of X-ray-Generated Impulses in Cylindrical Samples at the National Ignition Facility

Dynamic x-ray impulse experiments investigate how materials behave in extreme radiation environments. These experiments need an exceptionally high x-ray flux, and currently, only a few experimental facilities have the energy capacity to drive these effects in macroscopic volumes of material. One such facility is the National Ignition Facility (NIF), which leverages lasers to create high-intensity x-ray line-emission [1]. The x-rays deposit energy into a thin layer of a sample, causing rapid heating and subsequent expansion of vaporized material. The expansion causes a high strain-rate shock wave to propagate into the remaining cold material, which can cause material damage in transit or upon reflection from the sample rear surface. Most experiments have focused on the response of centimeter-scale coupons [2]. In this talk, we present results from a novel extension to the x-ray effects platform that characterizes for the first time the effects of NIF x-rays on 10 cm cylindrical samples. We identify how the impulse varies as a function of x-ray angle of incidence in the NIF target geometry and perform simulation studies to understand better the shock propagation properties. Results from these experiments pave the way for future analysis on x-ray delivered impulses in complex geometries and enable new regimes of model validation studies.

[1] M. J. May et al., Phys. Rev. E 111, 015201 (2025).

[2] D. Goto and S. J. Moon, LLNL-TR-817143 (2020).