Explosive detection systems

Human factors need to be properly considered in the design and appfication of any detection system. Studies have shown that explosive detection systems generally perform less effectively in realistic field trials than in laboratory tests and that one of the biggest causes of this shortfall is failure to properly consider the operator/ system interface. 

The requirements for an explosive detection system are set out in certification standards issued by the FAA/TSA/DHS. Key issues are as follows ... 

J. Bartko, P. H. Ruddy, A Review of the Development of a Luggage Explosive Detection System, Proceedings of the Seventh ASTM-Euratom Symposium on Reactor Dosimetry, G. Tsotridis, R. Dierckx, P. D Hondt (eds), Kluwer Academic Press, Dordrecht, The Netherlands, 1992. 

Environment Assessment of the Thermal Neutron Activation Explosive Detection System for Concourse Use at U.S.Airports, US Nuclear Regulatory Commission, NUREG-1396,... 

M. J. Hurwitz, W. P. Noronba, T. A. Atwell, Airport Testing of a New Thermal Neutron Analysis Explosives Detection System, Proceedings of the First International Symposium on Explosive Detection Technology, pp. 388—395, 13—15 November 1991. US Department of Transportation, February 1992. 

The Development of a Prototype High-Explosive Detection System Based on Nuclear Resonance Absorption (Project OPEB-A), Summary report, Soreq Nuclear Research Center., December 1993. 

R. E. Morgado, G. Amone, C. C. CappieUo, S. D. Gardner, C. L. Hollas, L. E. Ussery, J. M. White, J. D. Zahrt, R. A. Krauss, Prototype Explosives-Detection System Based on Nuclear Resonance Absorption in Nitrogen, Los Alamos National Laboratory, Report LA-12776-MS, Los Alamos, NM, June 1994. 

R.F. Eilbert, Development and evaluation of simulants for x-ray based explosive detection systems, in Proc. 2nd Explosives Detection Symposium Aviation Security Conference, W.H. Makky (ed.), 12-14 November 1996, Adantic City, NJ, FAA (1996) 49—54. 

These and other trade-offs have been successfully balanced by the design teams of currently certified X-ray CT explosives detection systems. The final sets of design parameters have been incorporated into CT inspection systems that are both effective and affordable. 

The main performance requirements of an explosive detection system are sensitivity, selectivity and speed of analysis. The mass spectrometer meets these requirements. Additional requirements are mobility and cost. During the last years, mass spectrometers have become smaller and mobile, but the prices are stiU relatively high. However, despite the complexity of the mass spectrometer, its performance as an explosives detector is more reliable than most existing vapor and trace detectors. 

Development and testing of the Hound II hand-portable explosives detection system. Proceedings of the 44th Annual Meeting of the Institute of Nuclear Materials Management, (2003) 43—50. 

Rhykerd, C. L., D. W. Hannum, D. W. Murray, and J. E. Parmeter. Guide for the Selection of Commercial Explosives Detection Systems for Law Enforcement Applications. NIJ Guide 100-99, NCJ 178913, National Institute of Justice, Office of Science and Technology, Washington, DC, 1999. 

Figure 9.4 Block diagram of the Fido explosives detection system.

Generally, the performance characteristics of greatest interest for an explosives detection system are sensitivity, selectivity, and response time. As used here, sensitivity is the ability to detect the target analyte in extremely small concentrations, while selectivity is the ability to distinguish the target analyte from other materials that may be present. In combination, good sensitivity and selectivity mean a high probability of detection when the analyte is present and a low false alarm rate when the analyte is not present. 

The commercially available Fido and Fido XT explosives detection systems are both handheld devices as shown in Figure 9.5. The Fido incorporates the sampling head directly into the body of the device. The XT version includes a tethered extension for the inlet that allows the sampling head to be separated from the rest of the instrument. The sampling head is mounted on a pistol grip so that sampling can be performed more conveniently (Fig. 9.6). 

Figure 9.5 The Fido X (left) and Fido XT (right) explosive detection systems.

Another enhancement in current development is preconcentration subsystems appropriate for Fido robot-deployed and handheld explosives detection systems. The primary Fido operational concept does not incorporate preconcentration, but clearly there are scenarios and applications where preconcentration will contribute to performance. To this end, integrated systems that will tightly couple AFP-based detection with MEMS-based preconcentration are under development. 

The detector was designed for automated and unattended operation and for use by nontechnical personnel. We present performance results for the QitTofMS explosives detection system in Section 11.4. 

Thermo Electron Corporation. A line of portable, bench-top explosives detection systems. EGIS II and EGIS III. Available at http //www.thermoramsey.de/EGIS-englisch.pdf. 

The mass spectrometer meets the main performance requirements of an explosive detection system, which are sensitivity, selectivity, and speed of analysis. Additional requirements are mobility and cost. 

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