Triboluminescent Probes for Determining Shock Arrival Time in Metal

Crushing, abrasion, and other mechanical deformation of solid materials can produce light: a phenomenon known as triboluminescence. This phenomenon was recently exploited to create a simple yet novel diagnostic for measuring the time of arrival of a shock front at a specific depth in a metal target. Two potential probe designs were built at Los Alamos National Laboratory, each using a different material as the triboluminescent agent. Both were tested at the Special Technologies Laboratory in Santa Barbara, CA in January 2022. The probes were embedded in an aluminum target and impacted with a tantalum flyer moving near 2.5 km/s, resulting in a shock speed and pressure of approximately 8 km/s and 40 GPa (respectively) in the aluminum. This talk will report results from the 5-shot campaign and consider whether this diagnostic approach could reduce the cost or complexity of determining time of arrival in future subcritical experiments.