Analysis of LIA Target Plasma Plume Energies via Mechanically Induced Plastic Membrane Deformation

The Dual Axis Radiography Hydrodynamic Test Facility (DARHT) consists of two linear induction accelerators (LIAs) to conduct flash radiography via bremsstrahlung X-ray production. The 60 us, 1.6 kA, 19.7 MeV electron beam produced in DARHT Axis 1 results in the vaporization of a tantalum converter target, which increases the risk of damage to surrounding beam imaging and diagnostic equipment. To quantify the risk of equipment damage, tests were conducted in 2021 to characterize the plume-surface interaction between the tantalum target and a 1 mm thick aluminum witness plate located about 1 cm downstream of the converter target. Deformations of up to 1.28 mm were measured on the witness plate. This study aims to characterize and quantify the energy deposition of the vaporized tantalum plume onto the witness plate through simulation and characteristic mechanical impact testing. To quantitatively assess the impact energy of the expanding target, we have designed and implemented a mechanical impactor that will allow us to interpret witness plate deformation across a range of boundary conditions. This experiment is supported by dynamic solvers and simulations such as Ansys LS-DYNA and FLAG. Combining simulations and experimentation, the target plume present in flash radiography accelerators can be better modeled for fundamental understanding of target dissociation dynamics and future upgrades to the DARHT facility.

LA-UR-25-27363