Benchtop Energetics: Detection of Hyperthermal Species
Abstract
We present a novel scheme for monitoring the transition between deflagration and "detonation-like" behavior of small-scale explosive samples subjected to shock stimuli. The intended geometry for this setup incorporates a laser-driven-flyer impact technique to generate a pure mechanical input. However, we report results here using a simplified geometry for purposes of evaluating the time-of-flight mass spectrometric (TOFMS) diagnostics using direct laser ablation of solid aluminum and of an aluminum mirror coated with a small amount (~1 microgram) of PETN. This manuscript presents the TOFMS detection of fast aluminum atoms (>10 km/s) resulting from laser ablation, confirming our ability to detect hyperthermal species. Preliminary results from pentaerythritol tetranitrate (PETN) experiments reveal a transition from species consistent with deflagration (primarily NO2) at low laser fluence, to those consistent with detonation-like events (N2 CO, CO2) at higher laser fluence. At this time, due to several unknown parameters in the current setup we will not posit the exact physical details which cause this transition (e.g. shock pressures temperatures, etc.). However, these results indicate that such a transition can be detected using the Benchtop Energetics TOFMS diagnostics setup, where future, more controlled and/or characterized energetic events may lead to better understanding of initiation/ignition thresholds of candidate materials.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2012
- Accession Number
- ADA570262
Entities
People
- Christopher D. Molek
- Emily C. Fossum
- Mario Fajardo
- William K Lewis
Organizations
- Air Force Research Laboratory