| AVS 62nd International Symposium & Exhibition | |
| Nanometer-scale Science and Technology | Wednesday Sessions |
| Session NS-WeM |
| Session: | Nanodiamond for Optical and Biomedical Applications |
| Presenter: | Trevor Willey, Lawrence Livermore National Laboratory |
| Authors: | T.M. Willey, Lawrence Livermore National Laboratory M. Bagge-Hansen, Lawrence Livermore National Laboratory L.M. Lauderbach, Lawrence Livermore National Laboratory R. Hodgin, Lawrence Livermore National Laboratory S. Bastea, Lawrence Livermore National Laboratory L. Fried, Lawrence Livermore National Laboratory A. Jones, Lawrence Livermore National Laboratory D. Hansen, Lawrence Livermore National Laboratory J. Benterou, Lawrence Livermore National Laboratory C. May, Lawrence Livermore National Laboratory T. Graber, Washington State University B.J. Jensen, Los Alamos National Laboratory D. Dattelbaum, Los Alamos National Laboratory R. Gustavsen, Los Alamos National Laboratory E. Watkins, Los Alamos National Laboratory M. Firestone, Los Alamos National Laboratory J. Ilavsky, Argonne National Laboratory T. van Buuren, Lawrence Livermore National Laboratory |
| Correspondent: | Click to Email |
Detonation is one of the primary methods to produce nanodiamond. A new small-angle x-ray scattering (SAXS) end station has been developed by LLNL for use at the new Dynamic Compression Sector at the Advanced Photon Source to observe carbon condensation during detonation of high explosives. The beamline and endstation are capable of synchronously initiating detonation and then acquiring up to four SAXS patterns from single x-ray pulses, which in 24-bunch mode at the APS are < 100 ps and arrive every 153.4 ns. Timescales are ideal: detonation investigation and model validation requires data regarding processes occurring at nanometer length scales on time scales ranging from nanoseconds to microseconds. The endstation and beamline have now demonstrated unprecedented fidelity in SAXS data during detonation; for the first time the data contains a clear Guinier knee and high-fidelity power law slope, giving information about the size and morphology of the resultant nanoparticles. We have commenced investigating HNS which is an explosive known to produce copious graphitic soots, RDX/TNT mixutures similar to what is commonly used to produce nanodiamond, and DNTF, a hydrogen-free, nitrogen rich, hot, and high velocity explosive. HNS produces carbon particles with a radius of gyration of 3 nm in less than 400 ns after the detonation front has passed, and this size is constant over the next several microseconds. The power-law slope is about -3, consistent with a disordered, irregular, or folded sp2 structure. Comp B, a 60% RDX, 40% TNT mixture, produces 3 nm particles also within a few hundred ns, and has a power law that is around -3.7, consistent with 3D nanodiamond particles. DNTF produces larger, 7 nm particles with a power law that is -4 over the first few hundred ns and then decreases to -3.8, ultimately also consistent with 3D diamond nanoparticles. In all three cases, particles are produced in the first few hundred ns, and then do not appreciably grow over the next several microseconds, which is in direct contradiction to previous pioneering work on RDX/TNT mixtures, TATB, and several other explosives, where observations indicate significant particle growth (50% or more) continues over several microseconds.