Comparing Existing and Novel Diagnostics for Determining Shock Arrival Time in Metal

Here we compare the performance of four diagnostics that can be used to determine the time of arrival of a shock wave in metal. These are the well-established TOAD (Time of Arrival Diagnostic) and PDV (Photon Doppler Velocimetry) probes of the types, as well as two novel probe types designed to indicate shock arrival by detecting triboluminescence in materials at their tips. All probes were built at Los Alamos National Laboratory and tested at the Special Technologies Laboratory in Santa Barbara, CA in January 2022. The probes were embedded in aluminum targets and impacted via with a tantalum flyer at a velocity of 2.5 km/s. The resulting shock speeds and pressures were approximately 8 km/s and approximately 40 GPa, respectively. This talk will report results from the 5-shot campaign and evaluate the merits of each probe type, culminating in recommendations for future subcritical and hydrodynamic experiments.