Wiley Handbook of Science and Technology for Homeland Security, 4 Volume Set

THREAT SIGNATURES OF EXPLOSIVE MATERIALS

LISA THEISEN

Contraband Detection, Sandia National Laboratories, Albuquerque, New Mexico

1 INTRODUCTION

Explosives detection systems can be categorized by application (e.g. detect explosives concealed on people, in packages, or in vehicles) as well as by technology (e.g. imaging or anomaly detection vs. trace detection). The unique characteristics of explosives have enabled researchers to develop a variety of explosives detection systems that capitalize on those properties that separate explosives from other materials. Properties such as vapor pressure, density, dielectric number, and effective atomic number are exploited in the detection of explosives.

Explosives detection methods are divided into two main technologies: trace detection and bulk detection. Trace detection technology searches for residue of explosives and bulk detection technology for larger amounts of explosives. Trace explosives techniques collect and analyze a sample of air or residue to detect explosive vapor and/or particles. The sample is collected and analyzed, and on the basis of a chemical analysis the material is detected. To generate a sample to collect and analyze, trace detection depends on vapor pressure. Sometimes taggants, which are additions to commercially manufactured explosives, can be the target for a successful trace detection. Bulk explosives techniques measure characteristics of the materials in question in an attempt to detect the possible presence ...