Development of Synthetic Radiochemistry Diagnostics

During the deceleration phase of an inertial confinement fusion (ICF) implosion, instability growth can lead to mixing between the ablator material and the thermonuclear fuel. Such mixing is undesirable, as it reduces the capsule's performance. One diagnostic approach for characterizing mix involves studying the x-ray emission from the burning fuel. However, this method becomes ineffective for targets containing high-Z materials surrounding the fuel, as these high-Z layers are opaque to x-rays. Nuclear diagnostics, including radiochemistry (RadChem) techniques, are being explored as alternative methods to assess mix. Among these, gaseous RadChem, enabled by the Radiochemical Analysis of Gaseous Samples (RAGS) detector at the National Ignition Facility (NIF), can provide mix information by quantifying gaseous products resulting from charged-particle reactions within ablator materials during thermonuclear burn. Synthetic RadChem diagnostic capabilities are being developed within the LANL radiation-hydrodynamics code xRAGE to support ICF applications, including the double-shell campaign. Recent progress toward the implementation of novel spatially and energetically discretized charged-particle flux tallying and RadChem postprocessing capabilities is summarized. Results are presented for selected charged-particle reactions involving light nuclei in exploding-pusher and double-shell designs and compared to available RadChem signatures measured by RAGS.