Characterization of energetic formulations optimized for optical initiation
- Los Alamos National Laboratory
Many experimental systems ignite energetic materials using lasers or other optical means. The ignition criteria can be different for each material, and will be dependent, at least, on the wavelength, power, energy density, and coherence of the light used. many of the more common energetic materials, such as HMX, PETN or RDX, are very poor light absorbers and are difficult to ignite optically, therefore the addition of a small amount ({approx} 1% by weight) of activated carbon aids in light absorption and thus ignition. However, these materials still suffer in terms of relatively large energy requirements and slow ignition times. Other materials, such ad DAATO{sub 3.5} (mixed N-oxide of 3,3-azo-bis(6-amino-1,2,4,5-tetrazine)), will ignite just from the energy supplied by a common camera flash, have very fast low-pressure burning rates, and due to decomposition mechanisms dominated by condensed phase reactions, have fast ignition times. Furthermore, the required ignition energies could be further reduced by the addition of nano-particulate transition metals (e.g. nano silver). by combining materials that are more optically sensitive with materials that are more explosively functional, interesting energetic systems with unique initiation criteria can be formulated. The optical characteristics of these formulations are examined using a 1064 nm Big Sky Nd:YAG laser and fiber optic system focused through a GRIN lens and into the sample, which is encased in a lexan holder. The energy from the laser is varied, from {approx} 0.7 mJ to {approx} 17 mJ, using neutral density filters, and is delivered in an {approx} 27.5 ns pulse. The energetic material is mixed with ethanol and slurry cast into the assembly. There are two types of ignition criteria detectable in these experiments. The first is a simple go/no-go criterion, in which any observable reaction is considered ignition, regardless of its violence. The second type requires both ignition and propagation of the reaction. By characterizing the energy required to initiate several different materials, more effective formulations can be designed using the better performing materials. Presented here are the results of laser initiation tests on a variety of compositions, principally combinations of PETN, DAATO{sub 3.5}, HMX, Ag{sub 2}BTA (silver bistetrazolamine), CuBTA, BNCP (bis-5-nitrotetrazolato tetraamine cobalt perchloriate), nm Ag, and a variety of MICs (metastable intermolecular compounds). Also presented are the conclusions as to which formulations are most suitable for optically initiated systems.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC52-06NA25396
- OSTI ID:
- 992164
- Report Number(s):
- LA-UR-10-01461; LA-UR-10-1461; TRN: US201022%%151
- Resource Relation:
- Conference: 14th international detonation symposium ; April 11, 2010 ; Coeur d'Alene, ID
- Country of Publication:
- United States
- Language:
- English
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