Conversion factors from counts to chemical ratios for the EURITRACK tagged neutron inspection system
| Autor: | W. El Kanawati, Jasmina Obhodas, Davorin Sudac, Cedric Carasco, Cyrille Eleon, Bertrand Perot, Vladivoj Valkovic |
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| Rok vydání: | 2011 |
| Předmět: |
Physics
Nuclear and High Energy Physics Isotope Astrophysics::High Energy Astrophysical Phenomena Monte Carlo method Gamma ray associated particle technique explosives and illicit drugs detection fast neutron interrogation material identification neutron moderation and photon attenuation in cargo containers Alpha particle Charged particle Neutron temperature Nuclear physics Nuclear fusion Neutron Instrumentation |
| Zdroj: | Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 654:621-629 |
| ISSN: | 0168-9002 |
| DOI: | 10.1016/j.nima.2011.05.076 |
| Popis: | The EURopean Illicit TRAfficking Countermeasures Kit (EURITRACK) uses 14 MeV neutrons produced by the 3 H(d,n) 4 H fusion reaction to detect explosives and narcotics in cargo containers. Reactions induced by fast neutrons produce gamma rays, which are detected in coincidence with the associated alpha particle to determine the neutron direction. In addition, the neutron path length is obtained from a time-of-flight measurement, thus allowing the origin of the gamma rays inside the container to be determined. Information concerning the chemical composition of the target material is obtained from the analysis of the energy spectrum. The carbon, oxygen, and nitrogen relative count contributions must be converted to chemical proportions to distinguish illicit and benign organic materials. An extensive set of conversion factors based on Monte Carlo numerical simulations has been calculated, taking into account neutron slowing down and photon attenuation in the cargo materials. An experimental validation of the method is presented by comparing the measured chemical fractions of known materials, in the form of bare samples or hidden in a cargo container, to their real chemical composition. Examples of application to real cargo containers are also reported, as well as simulated data with explosives and illicit drugs. |
| Databáze: | OpenAIRE |
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