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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-21 19:51 |
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Conference: Bucharest University Faculty of Physics 2008 Meeting
Section: Nuclear and Elementary Particles Physics
Title:
On the determination methods of the effective atomic numbers used in the security of the airports
Authors:
Mihai IOVEA, Marian NEAGU, Octavian DULIU, Madalina MANGU, Alexandru JIPA
Affiliation:
University of Bucharest, Faculty of Physics, Atomic and Nuclear Physics Chair
E-mail
mangumadalina@yahoo.com
Keywords:
Atomic effective number, explosive detection, DR, CT, Dual – Energy, luggage, screening.
Abstract:
In the last years, an interesting area of the computer tomography is the fast luggage control at airports for identification of the explosive materials and bombs. This control is based on the better determination of attenuation coefficients or effective atomic numbers for composite materials. For luggage control, a few methods have been substantially developed in the last years due to the increase of the security measures after the events from September 2001, in USA, and of a few attempts of terrorist attacks in Europa. In the present work, those methods based on has Digital Radioscopy (DR) and Computer Tomography (CT) are presented.
Dual energy method used in CT and DR is based on the attenuation coefficient measurements with X Rays sources at two energies, low and high energy. With dual energy X Rays CT the values of the density and the effective atomic number of the investigated materials can be establish. In the dual energy Digital Radioscopy the effective atomic number and the weight of the studied probes can be found. High performance CT scanner, called Dual Energy X Rays Tomograph, has been used for the measurements included in the present work. A 2% maximum relative error in effective atomic number measurements in DR have been obtained. Also, a 3% maximum relative error for effective atomic number and a 2% maximum relative error for density measurements have been obtained in CT tests. These results are useful in the identification of the interesting materials.
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