Time-resolved measurements of near infrared emission spectra from explosions: Pure pentaerythritol tetranitrate and its mixtures containing silver and aluminum particles

Abstract

Measurements of chemical transients and thermodynamic conditions are difficult to obtain yet fundamentally important in understanding the behavior of explosives. We have constructed a fast near infrared (NIR) spectrometer and have made temporally and spectrally-resolved emission measurements during postdetonation combustion of pure pentaerythritol tetranitrate (PETN) charges and PETN charges doped with 10 wt % microparticles composed of silver (Ag) and aluminum (Al). We have observed postdetonation PETN emission spectra between 750 and 1500 nm at rates up to 46 992 spectra/s. The instrument captures the highly structured spectra immediately following breakout as well as the longer-lived broadband NIR emission signals from hot particles. The early spectra reveal spectral signatures related to PETN and the reacting constituents of the particles. The later spectra provide a means to infer the gray-body temperature history of the particles.