Super-Sensitive Explosives Detector

Ion Mobility Spectrometers (IMS) are sensors used extensively to detect trace volatiles of explosives and chemical weapons. Developed in the 1970s, IMS has become a mainstay of explosives detection technology due to its low cost, rapid response and high sensitivity (parts per billion). Nonetheless, there is compelling need to develop more sensitive sensors that are field-deployable to meet the challenges of countermine and anti-terror defense. Greater sensitivity will enhance ability to detect explosive volatiles at greater distance from the source of emanation and will also enable detection of advanced explosives having low vapor pressure. We propose to develop a new form of IMS instrument based on Differential Mobility Analysis (DMA) to meet these challenges. Whereas IMS separates ions in time, the DMA separates them in space. This fundamentally new approach offers important advantages including potential for significantly enhanced sensitivity (<parts per trillion). As an adjunct to our development of the DMA, we will also explore use of secondary ionization by electro-spray as replacement for radioactive ionization sources necessary for conventional IMS thereby solving a significant logistical and safety problem. Phase I will produce results that will lay the foundation for Phase II development of a prototype robot-mounted DMA explosives sensor.