Nonintrusive cargo inspection

Billions of tons of cargo cross international borders and flow through ports every year in intermodal containers and semi-trailers. At present, the worldwide norm is to inspect these containers and vehicles using time-consuming and costly manual inspection. However, inspection samples are small and ineffective in stemming the flow of contraband and detecting import/export violations. To address this problem the Advanced Research Projects Agency (ARPA), an agency of the US Department of Defense, initiated a nonintrusive cargo inspection technology development program in 1991. The program included the operation of a test and demonstration facility in Houston, Texas from November 1991 through October 1992. It also included the design, construction and operation of a full-scale testbed in the port of Tacoma, Washington, where extensive tests of high-energy X-ray imaging system technology were conducted from May 1993 through December 1993. The prime contractor for the design, construction and operation of both the Houston and Tacoma facilities was Analytical Systems Engineering Corporation (ASEC). This paper presents an overview of the components of a high-energy X-ray imaging system and presents test results that demonstrate that high-energy X-ray inspection techniques can reliably detect contraband hidden within cargo, reliably detect variations between documented and actual cargo, allow a significantly greater percentage of cargo to be inspected, allow more thorough and faster inspections than by using manual means, and reduce inspection costs