Thermal Signature Measurements for Ammonium Nitrate/Fuel Mixtures by Laser Heating

Area of Science:

• Analytical Chemistry
• Materials Science
• Forensic Science

Background:

• Accurate identification of energetic materials is critical for safety and security.
• Existing methods for characterizing unknown energetic substances require improvement.
• Ammonium nitrate/fuel (ANF) mixtures are common energetic materials with varying compositions.

Purpose of the Study:

• To establish thermal signatures for various ammonium nitrate/fuel (ANF) mixtures.
• To develop a foundational dataset for a thermal-signature database.
• To enhance the identification of energetic substances with unknown compositions.

Main Methods:

• Utilized the laser-driven thermal reactor (LDTR) technique for thermal signature acquisition.
• Investigated ANF mixtures including AN/kerosene, AN/ethylene glycol, and AN/cellulose.
• Compared thermograms of mixtures with individual constituents and previously studied ANF formulations.

Main Results:

• Each ANF mixture exhibited a unique thermal signature, unambiguously linked to its composition.
• The thermal signature of a mixture was influenced by the thermal properties of its individual components.
• Experimental factors like residue coating and oxide layer changes affected baseline signatures, necessitating pre-oxidation.

Conclusions:

• Thermal signatures generated by the LDTR technique are effective for differentiating ANF mixtures.
• The study provides a basis for a comprehensive thermal-signature database for energetic materials.
• Understanding constituent contributions to thermal signatures is key for accurate identification.