Super-Sensitive Explosives Detector

The U.S. Military Services have urgent needs for improved technologies to detect mines, car bombs, and improvised explosive devices. Similar technologies are needed for homeland defense. Ion Mobility Spectrometers (IMS) are already 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 trace volatiles of explosives at greater distance from the source of emanation and will also enable detection of advanced explosives having low vapor pressure. In Phase I we have proven that a new form of IMS instrument based on Differential Mobility Analysis (DMA) can likely meet these challenges. Whereas IMS separates ions in time, the DMA separates them in space. This fundamentally new approach offers important advantages including significantly enhanced sensitivity (parts per trillion) as demonstrated in Phase I. As an adjunct to our development of the DMA, we will continue to 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 II will build on our success in Phase I, culminating in the development of a prototype robot-mounted DMA explosives sensor.