Experimental demonstration of multiple monoenergetic gamma radiography for effective atomic number identification in cargo inspection
Name
1.5025805.pdf
Description
Published version
Size
3.22 MB
Format
Adobe PDF
Checksum (MD5)
a56992026bb361f8cd4e41734d3a0b36
Author(s)
Henderson, Brian Scott
Lee, Hin Y.
MacDonald, Thomas D.
Nelson, Roberts Grafton.
Danagoulian, Areg
Date Issued
April 2018
Journal
Journal of Applied Physics
Publisher
AIP Publishing
Citation
Henderson, Brian S., et al., "Experimental demonstration of multiple monoenergetic gamma radiography for effective atomic number identification in cargo inspection." Journal of Applied Physics 123, 16 (2018) doi 10.1063/1.5025805 ©2018 Author(s)
Version
Final published version
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.
MIT Department
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
Terms of Use
Creative Commons Attribution 4.0 International license
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1063/1.5025805
