Using the Photoneutron Interaction to Detect Special Nuclear Material


N. E. Hertel, M. P. Shannon


The need to detect special nuclear material entering U.S. borders has become increasingly important as the nation continues to deal with the issue of nuclear terrorism. This study explores utilizing highly energetic photons to generate a photonuclear reaction in packages suspected of containing special nuclear material. The incident photon flux is bremsstrahlung created by striking a tungsten target with electrons from an electron accelerator. Several electron energies are explored, ranging from 6 to 15 MeV. The Los Alamos National Laboratory N-Particle Transport Code Extended (MCNPX) is used to model several scenarios involving U-235 in shielded and unshielded configurations. The neutron energy fluence generated by an empty container is compared against those resulting from a package containing U-235 with and without shielding. The data show that this technique has promise for use in this application; both the numbers and energy dependences of neutrons from the container correlate with the addition of U-235.


This abstract was presented at the 38th Annual Midyear Meeting, "Materials Control and Security: Risk Assessment, Handling, and Detection", Advances in Instrumentation, Materials Detection and Measurement Session, 2/13/2005 - 2/16/2005, held in New Orleans, LA.

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