Naslov
Inspection of shipping containers for threat materials

Autori
Valković, Vladivoj ; Blagus, Saša ; Sudac, Davorin ; Nađ, Karlo ; Matika, Dario

Izvornik
Radiation physics and chemistry (0969-806X) 71 (2004), 3/4; 897-898

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
illicit trafficing ; shipping containers ; alpha particle tagged neutron beams

Sažetak
In today's society acts of terrorism must involve in some stages the illicit trafficking either of explosives, narcotics, chemical weapons, hazardous chemicals, radioactive materials and/or humans. Therefore the society must rely on the modern anti-trafficking infrastructure including adequate instrumental base. Old control measures slow down the traffic flow, they are time consuming and inefficient. Recently lots of efforts has be put into development of the concept of "the smart border", border management system that keeps pace with expanding trade while protecting from the threats of terrorist attack, illegal immigration, illegal drugs, and other contraband. Due to the size of container transport industry the shipping container control system must be an essential building block of the smart border concept. The world's total movement in containers is estimated to be 72m TEU ("20-foot equivalent units"). A single typical large container ship can carry up to 6, 000 TEU. Although the container has become indispensable to world commerce, it also turned out to be handy ways to smuggle drugs, contraband and illegal immigrants. Modern cargo inspection systems are non-invasive imaging techniques, the inspection systems using penetrating radiations (1.33 MeV gamma and 0.3 and 0.45 MeV x-rays) in the scanning geometry. Relative penetration of the commonly used radiation is 17.5, 10.0 and 4.43 cm-iron for 1.33, 0.45 and 0.3 MeV, respectively. The concept of the multisensor system is based on the integrated use of gamma or x-ray fast scanning of the interrogated object (i.e. the whole container) with subsequent detailed elemental analysis of suspicious volumes by using fast neutrons. The use of alpha particle tagged neutron beams is a unique feature of such device in that it can enhance by a large factor the signal/noise ratio of the system. In the work reported here the neutron beam was obtained by means of D+T reaction. The associated alpha particle detector was fixed in such a way that the associated neutron beam was in horizontal plane at 90º ; ; ; to the deutron beam. Slit in front of the scintlillator was used to define the geometrical dimensions of the beam on the interrogated object. The α -γ coincidence spectra were measured with the selection of α -γ coincidences performed by the 100 ns TAC range. The information on the position of the interrogated object was contained in the TAC spectrum, while object's composition gave rise to characteristic gamma ray spectrum. In addition, conceptual design of the system, and preliminary data, for the inspection of the shipping containers for radioactive materials in the small to medium size container ports are reported. The aim was to detect the presence of shielded or unshielded sources inside the shipping container. This could be accomplished during the movement of the container: (i) from the ship to the storage area by radiation detector mounted on the crane and (ii) from the storage area while leaving the container port by track or train by gate monitors or by using gamma inspection systems in the passive mode.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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