Small-scale Characterization of Homemade Explosives (HMEs)
All explosives suffer from side-losses at the charge boundary. This makes each explosive material only able to perform if it is configured above a certain amount. This amount is small for military explosives, but many “homemade” explosives, especially the fuel-oxidizer mixtures, will only perform as explosives on very large scales. It is impractical to evaluate each potential threat material on the ton scale due to cost and safety. Furthermore, a ‘no-go’ result may not indicate the material is safe-just that a sufficiently large charge was not tested. A parallel problem is in the area of diluting or inerting explosive materials either for transport, demilitarization or storage. Once a diluent or treatment has been applied, the material may only have been rendered safer, but only large-scale testing can tell for sure.
Assurance of safety in both cases must be assessed on the small (1lb) scale; the characteristics of detonation chemistry must be identified in shocked samples configured well below their critical diameter. The propagation of chemistry must be observed in a microsecond-resolved temporal profile to measure things like run-up distance and detonation velocity. The observation of detonation chemistry can also be observed by instrumenting pressure gauges along the interior or terminus of the tube. This project is equipped to do these things on almost any mixture by using an adapted form of photon Doppler velocimetry (PDV). By using modern telecommunications components and optical devices, fiber optic cables transmit information about the detonation at picosecond temporal resolution. These suspect materials are being evaluated for their potential to behave as explosive materials, and inferences about the existence of a critical diameter can be made.
Steven F. Son
Students Currently Involved in Project
- David Kittell
- Peter Renslow