Photoacoustic Sensing of Explosives
Abstract
A modular, standoff, laser-induced acoustics system detects and discriminates trace amounts of explosive material. Photoacoustic Sensing of Explosives (PHASE) is a promising new technology that detects trace explosive residues from significant standoff distances, providing early warning of concealed threats targeting civilians, military personnel, and public facilities. PHASE exploits photoacoustic phenomena resulting from ultraviolet laser excitation. Exposed explosives are excited up to 100 meters away by using PHASE's ultraviolet laser. The high peak power causes explosives to dissociate, vaporize, and release into the near atmosphere, producing intense local pressure variances and consequent acoustic signals. In current practice, explosives screening is conducted manually, by visual inspection, by swabbing, and through X-ray analysis. Often, these inspections are random searches or depend on trained inspectors to select suspicious individuals. Current approaches can also be time-consuming, especially when screening individuals, containers, luggage, and packages one at a time in a conveyor-line approach. Although current techniques are successful, they are unable to cover all individuals, are difficult to implement for objects in large public areas, and are typically not covert. PHASE mitigates these problems by detecting and discriminating exposed trace explosives deposited on common surfaces from significant standoffs. It can locate explosive deposits to within several millimeters (in static mode or on moving objects such as vehicle door handles) at concentrations from bulk down to 200 ng/sq cm (partial fingerprint). PHASE is designed to operate covertly, perhaps from a hidden standoff location, to view vehicles, containers, packages, or baggage.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 2013
- Accession Number
- ADA594040
Entities
People
- Robert Haupt
Organizations
- Massachusetts Institute of Technology