Abstract
The smuggling of special nuclear materials (SNMs) through international borders could enable nuclear terrorism and constitutes a significant threat to global security. This paper presents the experimental demonstration of a novel radiographic technique for quantitatively reconstructing the density and type of material present in commercial cargo containers, as a means of detecting such threats. Unlike traditional techniques which use sources of bremsstrahlung photons with a continuous distribution of energies, multiple monoenergetic gamma radiography utilizes monoenergetic photons from nuclear reactions, specifically the 4.4 and 15.1 MeV photons from the 11B(d,nγ)12C reaction. By exploiting the Z-dependence of the photon interaction cross sections at these two specific energies, it is possible to simultaneously determine the areal density and the effective atomic number as a function of location for a 2D projection of a scanned object. The additional information gleaned from using and detecting photons of specific energies for radiography substantially increases the resolving power between different materials. This paper presents results from the imaging of mock cargo materials ranging from Z≈5−92, demonstrating accurate reconstruction of the effective atomic number and areal density of the materials over the full range. In particular, the system is capable of distinguishing pure materials with Z≳70, such as lead and uranium—a critical requirement of a system designed to detect SNM. This methodology could be used to screen commercial cargoes with high material specificity, to distinguish most benign materials from SNM, such as uranium and plutonium.
Highlights
The field of nuclear security addresses the danger of the nuclear weapons, including proliferation of weapon technology, safeguards of fissile materials, and the risk of nuclear terrorism
The technique is capable of separating benign high-Z materials such as lead and tungsten from special nuclear materials (SNMs)
WORK The results presented here establish the use of multiple monoenergetic gamma ray radiography (MMGR) to image materials in both their effective atomic number and areal density
Summary
The field of nuclear security addresses the danger of the nuclear weapons, including proliferation of weapon technology, safeguards of fissile materials, and the risk of nuclear terrorism. The latter topic encompasses cargo security, which focuses on preventing the smuggling of nuclear materials and fully assembled nuclear devices through ports of entry and other pathways. This paper details the demonstration of a new radiography technique for quantitatively identifying materials in cargo that is capable of distinguishing different materials with high atomic number. The technique is capable of separating benign high-Z materials such as lead and tungsten from special nuclear materials (SNMs)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
