Citation

Vlaković V, Sudac D, Matika D. Promet 2006; 18(3): 235-244.

Copyright

(Copyright © 2006, Faculty of Traffic and Transport Sciences, University of Zagreb)

DOI

10.7307/ptt.v18i3.692

PMID

unavailable

Abstract

Illicit trafficking of threat materials, especially explosives, chemical substances and radioactive or nuclear material. The transport of the threat materials by using sea routes is an advantage to terrorists especially because of the possible use of ship containers.The container is the basis of world trade. It is assumed that the world total movement in containers is about 200 million TEUs ("20-foot equivalent units") per year. The list of materials transported by containers which should be subject to inspection with the aim of reducing the acts of terrorism includes explosives, narcotics, chemical weapons, hazardous chemicals and radioactive materials. Of special interest is nuclear terrorism. The risk of nuclear terrorism carried out by sub-national groups should be considered not only in the construction and/or use of nuclear device, but also in possible radioactive contamination of large urban areas.The system of ship containers control is an essential component of "smart border" concept. Modem personnel, parcel, vehicle and cargo inspection systems are non-invasive imaging techniques based on the use of nuclear analytical techniques.The inspection systems use penetrating radiations: hard x-rays (300 keV or more) or gamma-rays from radioactive sources (137Cs and 60Co with energies from 600 to 1300 keV) that produce a high resolution radiograph of the load. Unfortunately, this information is "non-specific" in that it gives no informationon the nature of objects that do not match_ the travel documents and are not recognized by a visual analysis of the radiographic picture. Moreover, there are regions of the container where x and gamma-ray systems are "blind" due to the high average atomic number of the objects irradiated that appear as black spots in the radiographic image. The systems being developed are based on the use of fast, 14Me V, neutrons with detection of associated a-particle from nuclear reaction by which neutrons are produced (d+t>a+n). In such a way the possibility to determine object location inside a closed container is obtained. This information is contained in the measured time interval between the detection of the associated a-particle and the detection of y-rays produced by neutronsin the investigated object by (n, y) and/or (n, n'y) reactions.The object identification is performed by the analysis ofcoincidence gamma rays energy spectrum. Results obtained so far on the implementation of NATOSfP-980526 project "Control of Illicit Trafficking in ThreatMaterials" and EU FP6 project "European Illicit Trafficking Countermeasures Kit, EURITRACK" have shown that it is possible to construct a multisensor system with a fast controlsensor using x-rays (whole container) followed by detailed elemental analysis of suspect volume by a neutron sensor.

Language: en