Hyperspectral imaging of energetic material microstructures under shock compression

As the primary mechanism for the ignition and initiation of polymer-bonded explosives during dynamic compression, the generation and propagation of hot spots in these materials are small and hardly observed with conventional experimental techniques. Here, we developed a hyperspectral imaging system that was combined with a shock compression microscope to observe the hot spots and obtain the spatial distribution of the temperature and emissivity of individual explosive microcrystals embedded in polymer matrix. We launched dynamic compressions with an aluminum flyer plate (500 µm diameter, 37 µm thick) that was accelerated to 3.6 km/s by a flat-top pulsed laser. The spatial distribution of the broadband thermal-emission signals from the explosive microcrystal denoted HMX (cyclotetramethylene-tetranitramine) of 200-300 µm in size, was captured by a multi-channel ultra-fast camera. By applying different color filters for different channels and capturing auto-emission images at different times, we generated videos of the spatial distributions of color temperature and emissivity on explosive microcrystals.