Accurate and timely detection of explosives, energetic materials, and their associated compounds would provide
valuable information to military commanders in a wide range of military operations: protection of fast moving
convoys from mobile or static IED threats; more deliberate countermine and counter-IED operations during
route or area clearance; and static roles such as hasty or deliberate checkpoints, critical infrastructure protection
and support to public security.
The detection of hidden explosive hazards is an extremely challenging problem, as evidenced by the fact that
related research has been ongoing in many countries for at least seven decades and no general purpose solution
has yet been found. Technologies investigated have spanned all major scientific fields, with emphasis on the
physical sciences, life sciences, engineering, robotics, computer technology and mathematics.
This paper will present a limited, operationally-focused overview of the current status of detection technologies.
Emphasis will be on those technologies that directly detect the explosive hazard, as opposed to those that
detect secondary properties of the threat, such as the casing, associated wires or electronics. Technologies that
detect explosives include those based on nuclear radiation and terahertz radiation, as well as trace and biological
detection techniques. Current research areas of the authors will be used to illustrate the practical applications.
TNO Human Factors in the Netherlands developed a prototype apparatus for testing the image quality of X-ray Baggage Screening Systems: BAXSTER. BAXSTER stands for BAggage X-ray Screening TesteR. The test has a variety of applications, e.g. support by the choice of optimal screening systems for airport security, comparison of competing X-ray systems, delivery tests and routine tests. Advantages over existing tests are (1) a strong relationship with real object recognition, (2) accurate and objective test results, and (3) ease of use: performing a test is almost as easy as doing an eye test at the optometrist. BAXSTER is based on the patented TOD (Triangle Orientation Discrimination) test method, which is well-suited for standardization, and development of the test apparatus was funded by the US FAA/TSA (Transportation Security Administration). The apparatus consists of two parts. The first part is a set of test charts containing triangular test patterns of various metals of different sizes and thicknesses. These charts are placed in a frame that is scanned by the X-ray system like a regular baggage item. The operator has to judge the orientation of these patterns on the X-ray image. The second part is a laptop with peripherals and software that controls and analyses the test. The result of a test is a set of performance indicators (relating to detection, resolution, penetration, wire detection and wire penetration) for the entire system, including the display, the operator and the effect of environmental conditions. No (electronic) connection with the X-ray system is required. The effectiveness of automatic object detection and material discrimination through dual-energy X-ray analysis cannot be tested with BAXSTER. In conclusion: with BAXSTER the image quality of X-ray Baggage Screening Systems can be tested easily and objectively.