Measurement of carbon condensates using small-angle x-ray scattering during detonation of the high explosive hexanitrostilbene

• Published in: Journal of applied physics 2015-06, Vol.117 (24)
• Main Authors: Bagge-Hansen, M., Lauderbach, L., Hodgin, R., Bastea, S., Fried, L., Jones, A., van Buuren, T., Hansen, D., Benterou, J., May, C., Graber, T., Jensen, B. J., Ilavsky, J., Willey, T. M.
• Format: Article
• Language: English
• Subjects: Applied physics; cameras; Carbon; Condensates; condensation; Detonation; Explosives; Foils; Gyration; Hexanitrostilbene; Morphology; Nanoparticles; particle scattering; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Power law; RDX; Scattering angle; Small angle X ray scattering; TATB; Thermal stability; X-ray scattering
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4922866

The dynamics of carbon condensation in detonating high explosives remains controversial. Detonation model validation requires data for processes occurring at nanometer length scales on time scales ranging from nanoseconds to microseconds. A new detonation endstation has been commissioned to acquire and provide time-resolved small-angle x-ray scattering (SAXS) from detonating explosives. Hexanitrostilbene (HNS) was selected as the first to investigate due to its ease of initiation using exploding foils and flyers, vacuum compatibility, high thermal stability, and stoichiometric carbon abundance that produces high carbon condensate yields. The SAXS data during detonation, collected with 300 ns time resolution, provide unprecedented signal fidelity over a broad q-range. This fidelity permits the first analysis of both the Guinier and Porod/power-law regions of the scattering profile during detonation, which contains information about the size and morphology of the resultant carbon condensate nanoparticles. To bolster confidence in these data, the scattering angle and intensity were additionally cross-referenced with a separate, highly calibrated SAXS beamline. The data show that HNS produces carbon particles with a radius of gyration of 2.7 nm in less than 400 ns after the detonation front has passed, and this size and morphology are constant over the next several microseconds. These data directly contradict previous pioneering work on RDX/TNT mixtures and TATB, where observations indicate significant particle growth (50% or more) continues over several microseconds. The power-law slope is about −3, which is consistent with a complex disordered, irregular, or folded sp2 sub-arrangement within a relatively monodisperse structure possessing radius of gyration of 2.7 nm after the detonation of HNS.