ALERT | Awareness and Localization of Explosive-Related Threats

Stability of Gas Ions of Explosives in Air at Ambient Pressure [INACTIVE]
R2-A2

Download Project Report (Phase 2, Year 5).

Project Description

[CONCLUDED Year 5]

Explosive Trace Detectors (ETDs), technology used in airports to detect explosives in the air, are dependent on the vaporization of explosive particulate, the ionization of these vapors, and subsequent measurement of the ions for characteristic mobilities in weak electric fields. The aim of this project is to provide pioneering thermochemical values for the stability of gas phase ions derived from explosives in air at ambient pressure and temperatures found in Explosive Trace Detectors (ETDs).

These ions have lifetimes on the millisecond time scales, meaning that they will quickly decompose into undetectable products. Thus, knowledge of the lifetimes and their dependences on temperature in air at ambient pressure is vital for understanding the response of existing ETDs and for building the foundations for the design of new ETDs.

In this project, we have developed technology and methods that allow us to determine lifetimes and other parameters that tell us about the rates of decomposition of gas ions of explosives under conditions identical to those inside the more than 20,000 ETDs distributed in airports worldwide.

These measurements have established first ever understandings and parameters for decomposition of explosive ions. In our first stage, a broad range of explosive materials was examined and detailed measurements made for nitroesters. In the next stage, we are examining some substances not immediately accessible to characterization and extending into materials used in improvised explosive devices (IEDs).