Hot Spot and Reaction Temperature of Insensitive High Explosives using Time-Resolved Optical Pyrometry

The capability of time-resolved optical pyrometry of our dynamic shock microscope system enables us to explore the evolution of the hot spot and combustion temperatures of shocked insensitive high explosives with nanosecond time resolution. Primarily, we analyze plastic-bonded explosive (PBX) formulations of triaminotrinitrobenzene (TATB), 1,1-diamino-2,2-dinitroethene (FOX-7), and 2,6-Diamino-3,5-Dinitropyrazine-1-Oxide (LLM-105). These explosives are particularly interesting because they are powerful but insensitive to accidental initiation. These three insensitive explosives have a yellow color, which causes a significant absorption in the blue region of the visible spectrum. This deviation from thermal radiation complicates the pyrometry experiment and should be accounted for in the determination of the temperature.
The experiments used short-duration (4 ns) shocks using laser-launched flyer plates with velocities of 1-4.5 km/s. The dynamic shock microscope system has, in addition to the optical pyrometer, a high-speed Photon Doppler Velocimeter (PDV), high-speed imaging cameras. We have developed methods to mass-produce tiny well-characterized PBX charges in arrays with hundreds of charges. The tiny charges were 80% explosive and 20% binder.